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C. J. Youn - One of the best experts on this subject based on the ideXlab platform.

  • Behavior of temperature-dependent dc-photoconductivity in hot-wall deposited CaAl_2Se_4 layers
    Journal of the Korean Physical Society, 2017
    Co-Authors: J. W. Jeong, K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The dc-photoconductive characteristic on the hot-wall grown CaAl_2Se_4 (CAS) layers was explored as a function of temperature. From the photocurrent (PC) measurement, three PC peaks A, B, and C corresponded to the intrinsic transitions, which represent the Band-to-Band transitions from the valence-Band States of Γ_2(A), Γ_3 + Γ_4(B), and Γ_3 + Γ_4(C) to the Conduction-Band State of Γ_1, respectively. Based on these PC results, the optical Band-gap energy was well matched by E _ g ( T ) = E _ g (0) − 4.94 × 10^−3 T ^2/( T + 552), where E _ g (0) is found to be 3.8239, 3.8716, and 3.8801 eV for three peaks A, B, and C, respectively. Thus, the effect of the crystal field and spin-orbit splitting (These values were extracted out to be 47.7 and 8.5 meV, respectively.) was observed and calculated by means of the PC spectroscopy. However, PC intensity gradually decreased with decreasing temperature unlike an ordinary behavior. In the log J _ ph vs 1/ T plot, two dominant traplevels were observed to be 20.81 meV at temperatures of 300 - 70 K and 1.18 meV at temperatures below 70 K. Consequently, we extract out that these trapping centers caused by native defects in CAS confine the PC intensity as temperature decreases.

  • Behavior of temperature-dependent dc-photoconductivity in hot-wall deposited CaAl 2 Se 4 layers
    Journal of the Korean Physical Society, 2017
    Co-Authors: Junwoo Jeong, K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The dc-photoconductive characteristic on the hot-wall grown CaAl2Se4 (CAS) layers was explored as a function of temperature. From the photocurrent (PC) measurement, three PC peaks A, B, and C corresponded to the intrinsic transitions, which represent the Band-to-Band transitions from the valence-Band States of Γ2(A), Γ3 + Γ4(B), and Γ3 + Γ4(C) to the Conduction-Band State of Γ1, respectively. Based on these PC results, the optical Band-gap energy was well matched by E g (T) = E g (0) − 4.94 × 10−3 T 2/(T + 552), where E g (0) is found to be 3.8239, 3.8716, and 3.8801 eV for three peaks A, B, and C, respectively. Thus, the effect of the crystal field and spin-orbit splitting (These values were extracted out to be 47.7 and 8.5 meV, respectively.) was observed and calculated by means of the PC spectroscopy. However, PC intensity gradually decreased with decreasing temperature unlike an ordinary behavior. In the log J ph vs 1/T plot, two dominant traplevels were observed to be 20.81 meV at temperatures of 300 - 70 K and 1.18 meV at temperatures below 70 K. Consequently, we extract out that these trapping centers caused by native defects in CAS confine the PC intensity as temperature decreases.

  • An analysis of temperature-dependent absorption and photocurrent spectra in BaAl2Se4 layers
    Journal of Applied Physics, 2015
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn, J. D. Moon
    Abstract:

    The temperature-dependent photoresponse behavior of BaAl2Se4 layers has been investigated through the analysis of optical absorption and photocurrent (PC) spectra. Based on these results, the optical Band gap was well expressed by Eg(T) = Eg(0) − 4.39 × 10−4T2/(T + 250), where Eg(0) is estimated to be 3.4205, 3.6234, and 3.8388 eV for the transitions corresponding to the valence Band States Γ3(A), Γ4(B), and Γ5(C), respectively. From the PC measurement, three peaks A, B, and C corresponded with the intrinsic transitions from the valence Band States of Γ3(A), Γ4(B), and Γ5(C) to the Conduction Band State of Γ1, respectively. According to the selection rule, the crystal field and spin orbit splitting were found to be 0.2029 and 0.2154 eV, respectively, through the direct use of PC spectroscopy. However, the PC intensities decreased with lowering temperature. In the log Jph versus 1/T plot, the dominant trap level at the high-temperature region was observed and its value was 12.7 meV. This level corresponds ...

  • Photocurrent Spectroscopic Study of Temperature-Dependent Photoresponse and Valence-Band Splitting in MnAl_2S_4 Layers
    Journal of Electronic Materials, 2014
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The temperature-dependent photoresponse characteristics of MnAl_2S_4 layers have been investigated, for the first time, by use of photocurrent (PC) spectroscopy. Three peaks were observed at all temperatures. The electronic origin of these peaks was associated with Band-to-Band transitions from the valence-Band States Γ_4( z ), Γ_5( x ), and Γ_5( y ) to the Conduction-Band State Γ_1( s ). On the basis of the relationship between PC-peak energy and temperature, the optical Band gap could be well expressed by the expression E _g( T ) =  E _g(0) − 2.80 × 10^−4 T ^2/(287 +  T ), where E _g(0) was estimated to be 3.7920 eV, 3.7955 eV, and 3.8354 eV for the valence-Band States Γ_4( z ), Γ_5( x ), and Γ_5( y ), respectively. Results from PC spectroscopy revealed the crystal-field and spin–orbit splitting were 3.5 meV and 39.9 meV. The gradual decrease of PC intensity with decreasing temperature can be explained on the basis of trapping centers associated with native defects in the MnAl_2S_4 layers. Plots of log J _ph, the PC current density, against 1/ T , revealed a dominant trap level in the high-temperature region. By comparing PC and the Hall effect results, we confirmed that this trap level is a shallow donor 18.9 meV below the Conduction Band.

  • Photocurrent Spectroscopic Study of Temperature-Dependent Photoresponse and Valence-Band Splitting in MnAl2S4 Layers
    Journal of Electronic Materials, 2014
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The temperature-dependent photoresponse characteristics of MnAl2S4 layers have been investigated, for the first time, by use of photocurrent (PC) spectroscopy. Three peaks were observed at all temperatures. The electronic origin of these peaks was associated with Band-to-Band transitions from the valence-Band States Γ4(z), Γ5(x), and Γ5(y) to the Conduction-Band State Γ1(s). On the basis of the relationship between PC-peak energy and temperature, the optical Band gap could be well expressed by the expression E g(T) = E g(0) − 2.80 × 10−4 T 2/(287 + T), where E g(0) was estimated to be 3.7920 eV, 3.7955 eV, and 3.8354 eV for the valence-Band States Γ4(z), Γ5(x), and Γ5(y), respectively. Results from PC spectroscopy revealed the crystal-field and spin–orbit splitting were 3.5 meV and 39.9 meV. The gradual decrease of PC intensity with decreasing temperature can be explained on the basis of trapping centers associated with native defects in the MnAl2S4 layers. Plots of log J ph, the PC current density, against 1/T, revealed a dominant trap level in the high-temperature region. By comparing PC and the Hall effect results, we confirmed that this trap level is a shallow donor 18.9 meV below the Conduction Band.

K. J. Hong - One of the best experts on this subject based on the ideXlab platform.

  • Behavior of temperature-dependent dc-photoconductivity in hot-wall deposited CaAl_2Se_4 layers
    Journal of the Korean Physical Society, 2017
    Co-Authors: J. W. Jeong, K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The dc-photoconductive characteristic on the hot-wall grown CaAl_2Se_4 (CAS) layers was explored as a function of temperature. From the photocurrent (PC) measurement, three PC peaks A, B, and C corresponded to the intrinsic transitions, which represent the Band-to-Band transitions from the valence-Band States of Γ_2(A), Γ_3 + Γ_4(B), and Γ_3 + Γ_4(C) to the Conduction-Band State of Γ_1, respectively. Based on these PC results, the optical Band-gap energy was well matched by E _ g ( T ) = E _ g (0) − 4.94 × 10^−3 T ^2/( T + 552), where E _ g (0) is found to be 3.8239, 3.8716, and 3.8801 eV for three peaks A, B, and C, respectively. Thus, the effect of the crystal field and spin-orbit splitting (These values were extracted out to be 47.7 and 8.5 meV, respectively.) was observed and calculated by means of the PC spectroscopy. However, PC intensity gradually decreased with decreasing temperature unlike an ordinary behavior. In the log J _ ph vs 1/ T plot, two dominant traplevels were observed to be 20.81 meV at temperatures of 300 - 70 K and 1.18 meV at temperatures below 70 K. Consequently, we extract out that these trapping centers caused by native defects in CAS confine the PC intensity as temperature decreases.

  • Behavior of temperature-dependent dc-photoconductivity in hot-wall deposited CaAl 2 Se 4 layers
    Journal of the Korean Physical Society, 2017
    Co-Authors: Junwoo Jeong, K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The dc-photoconductive characteristic on the hot-wall grown CaAl2Se4 (CAS) layers was explored as a function of temperature. From the photocurrent (PC) measurement, three PC peaks A, B, and C corresponded to the intrinsic transitions, which represent the Band-to-Band transitions from the valence-Band States of Γ2(A), Γ3 + Γ4(B), and Γ3 + Γ4(C) to the Conduction-Band State of Γ1, respectively. Based on these PC results, the optical Band-gap energy was well matched by E g (T) = E g (0) − 4.94 × 10−3 T 2/(T + 552), where E g (0) is found to be 3.8239, 3.8716, and 3.8801 eV for three peaks A, B, and C, respectively. Thus, the effect of the crystal field and spin-orbit splitting (These values were extracted out to be 47.7 and 8.5 meV, respectively.) was observed and calculated by means of the PC spectroscopy. However, PC intensity gradually decreased with decreasing temperature unlike an ordinary behavior. In the log J ph vs 1/T plot, two dominant traplevels were observed to be 20.81 meV at temperatures of 300 - 70 K and 1.18 meV at temperatures below 70 K. Consequently, we extract out that these trapping centers caused by native defects in CAS confine the PC intensity as temperature decreases.

  • An analysis of temperature-dependent absorption and photocurrent spectra in BaAl2Se4 layers
    Journal of Applied Physics, 2015
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn, J. D. Moon
    Abstract:

    The temperature-dependent photoresponse behavior of BaAl2Se4 layers has been investigated through the analysis of optical absorption and photocurrent (PC) spectra. Based on these results, the optical Band gap was well expressed by Eg(T) = Eg(0) − 4.39 × 10−4T2/(T + 250), where Eg(0) is estimated to be 3.4205, 3.6234, and 3.8388 eV for the transitions corresponding to the valence Band States Γ3(A), Γ4(B), and Γ5(C), respectively. From the PC measurement, three peaks A, B, and C corresponded with the intrinsic transitions from the valence Band States of Γ3(A), Γ4(B), and Γ5(C) to the Conduction Band State of Γ1, respectively. According to the selection rule, the crystal field and spin orbit splitting were found to be 0.2029 and 0.2154 eV, respectively, through the direct use of PC spectroscopy. However, the PC intensities decreased with lowering temperature. In the log Jph versus 1/T plot, the dominant trap level at the high-temperature region was observed and its value was 12.7 meV. This level corresponds ...

  • Photocurrent Spectroscopic Study of Temperature-Dependent Photoresponse and Valence-Band Splitting in MnAl_2S_4 Layers
    Journal of Electronic Materials, 2014
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The temperature-dependent photoresponse characteristics of MnAl_2S_4 layers have been investigated, for the first time, by use of photocurrent (PC) spectroscopy. Three peaks were observed at all temperatures. The electronic origin of these peaks was associated with Band-to-Band transitions from the valence-Band States Γ_4( z ), Γ_5( x ), and Γ_5( y ) to the Conduction-Band State Γ_1( s ). On the basis of the relationship between PC-peak energy and temperature, the optical Band gap could be well expressed by the expression E _g( T ) =  E _g(0) − 2.80 × 10^−4 T ^2/(287 +  T ), where E _g(0) was estimated to be 3.7920 eV, 3.7955 eV, and 3.8354 eV for the valence-Band States Γ_4( z ), Γ_5( x ), and Γ_5( y ), respectively. Results from PC spectroscopy revealed the crystal-field and spin–orbit splitting were 3.5 meV and 39.9 meV. The gradual decrease of PC intensity with decreasing temperature can be explained on the basis of trapping centers associated with native defects in the MnAl_2S_4 layers. Plots of log J _ph, the PC current density, against 1/ T , revealed a dominant trap level in the high-temperature region. By comparing PC and the Hall effect results, we confirmed that this trap level is a shallow donor 18.9 meV below the Conduction Band.

  • Photocurrent Spectroscopic Study of Temperature-Dependent Photoresponse and Valence-Band Splitting in MnAl2S4 Layers
    Journal of Electronic Materials, 2014
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The temperature-dependent photoresponse characteristics of MnAl2S4 layers have been investigated, for the first time, by use of photocurrent (PC) spectroscopy. Three peaks were observed at all temperatures. The electronic origin of these peaks was associated with Band-to-Band transitions from the valence-Band States Γ4(z), Γ5(x), and Γ5(y) to the Conduction-Band State Γ1(s). On the basis of the relationship between PC-peak energy and temperature, the optical Band gap could be well expressed by the expression E g(T) = E g(0) − 2.80 × 10−4 T 2/(287 + T), where E g(0) was estimated to be 3.7920 eV, 3.7955 eV, and 3.8354 eV for the valence-Band States Γ4(z), Γ5(x), and Γ5(y), respectively. Results from PC spectroscopy revealed the crystal-field and spin–orbit splitting were 3.5 meV and 39.9 meV. The gradual decrease of PC intensity with decreasing temperature can be explained on the basis of trapping centers associated with native defects in the MnAl2S4 layers. Plots of log J ph, the PC current density, against 1/T, revealed a dominant trap level in the high-temperature region. By comparing PC and the Hall effect results, we confirmed that this trap level is a shallow donor 18.9 meV below the Conduction Band.

T. S. Jeong - One of the best experts on this subject based on the ideXlab platform.

  • Behavior of temperature-dependent dc-photoconductivity in hot-wall deposited CaAl_2Se_4 layers
    Journal of the Korean Physical Society, 2017
    Co-Authors: J. W. Jeong, K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The dc-photoconductive characteristic on the hot-wall grown CaAl_2Se_4 (CAS) layers was explored as a function of temperature. From the photocurrent (PC) measurement, three PC peaks A, B, and C corresponded to the intrinsic transitions, which represent the Band-to-Band transitions from the valence-Band States of Γ_2(A), Γ_3 + Γ_4(B), and Γ_3 + Γ_4(C) to the Conduction-Band State of Γ_1, respectively. Based on these PC results, the optical Band-gap energy was well matched by E _ g ( T ) = E _ g (0) − 4.94 × 10^−3 T ^2/( T + 552), where E _ g (0) is found to be 3.8239, 3.8716, and 3.8801 eV for three peaks A, B, and C, respectively. Thus, the effect of the crystal field and spin-orbit splitting (These values were extracted out to be 47.7 and 8.5 meV, respectively.) was observed and calculated by means of the PC spectroscopy. However, PC intensity gradually decreased with decreasing temperature unlike an ordinary behavior. In the log J _ ph vs 1/ T plot, two dominant traplevels were observed to be 20.81 meV at temperatures of 300 - 70 K and 1.18 meV at temperatures below 70 K. Consequently, we extract out that these trapping centers caused by native defects in CAS confine the PC intensity as temperature decreases.

  • Behavior of temperature-dependent dc-photoconductivity in hot-wall deposited CaAl 2 Se 4 layers
    Journal of the Korean Physical Society, 2017
    Co-Authors: Junwoo Jeong, K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The dc-photoconductive characteristic on the hot-wall grown CaAl2Se4 (CAS) layers was explored as a function of temperature. From the photocurrent (PC) measurement, three PC peaks A, B, and C corresponded to the intrinsic transitions, which represent the Band-to-Band transitions from the valence-Band States of Γ2(A), Γ3 + Γ4(B), and Γ3 + Γ4(C) to the Conduction-Band State of Γ1, respectively. Based on these PC results, the optical Band-gap energy was well matched by E g (T) = E g (0) − 4.94 × 10−3 T 2/(T + 552), where E g (0) is found to be 3.8239, 3.8716, and 3.8801 eV for three peaks A, B, and C, respectively. Thus, the effect of the crystal field and spin-orbit splitting (These values were extracted out to be 47.7 and 8.5 meV, respectively.) was observed and calculated by means of the PC spectroscopy. However, PC intensity gradually decreased with decreasing temperature unlike an ordinary behavior. In the log J ph vs 1/T plot, two dominant traplevels were observed to be 20.81 meV at temperatures of 300 - 70 K and 1.18 meV at temperatures below 70 K. Consequently, we extract out that these trapping centers caused by native defects in CAS confine the PC intensity as temperature decreases.

  • An analysis of temperature-dependent absorption and photocurrent spectra in BaAl2Se4 layers
    Journal of Applied Physics, 2015
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn, J. D. Moon
    Abstract:

    The temperature-dependent photoresponse behavior of BaAl2Se4 layers has been investigated through the analysis of optical absorption and photocurrent (PC) spectra. Based on these results, the optical Band gap was well expressed by Eg(T) = Eg(0) − 4.39 × 10−4T2/(T + 250), where Eg(0) is estimated to be 3.4205, 3.6234, and 3.8388 eV for the transitions corresponding to the valence Band States Γ3(A), Γ4(B), and Γ5(C), respectively. From the PC measurement, three peaks A, B, and C corresponded with the intrinsic transitions from the valence Band States of Γ3(A), Γ4(B), and Γ5(C) to the Conduction Band State of Γ1, respectively. According to the selection rule, the crystal field and spin orbit splitting were found to be 0.2029 and 0.2154 eV, respectively, through the direct use of PC spectroscopy. However, the PC intensities decreased with lowering temperature. In the log Jph versus 1/T plot, the dominant trap level at the high-temperature region was observed and its value was 12.7 meV. This level corresponds ...

  • Photocurrent Spectroscopic Study of Temperature-Dependent Photoresponse and Valence-Band Splitting in MnAl_2S_4 Layers
    Journal of Electronic Materials, 2014
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The temperature-dependent photoresponse characteristics of MnAl_2S_4 layers have been investigated, for the first time, by use of photocurrent (PC) spectroscopy. Three peaks were observed at all temperatures. The electronic origin of these peaks was associated with Band-to-Band transitions from the valence-Band States Γ_4( z ), Γ_5( x ), and Γ_5( y ) to the Conduction-Band State Γ_1( s ). On the basis of the relationship between PC-peak energy and temperature, the optical Band gap could be well expressed by the expression E _g( T ) =  E _g(0) − 2.80 × 10^−4 T ^2/(287 +  T ), where E _g(0) was estimated to be 3.7920 eV, 3.7955 eV, and 3.8354 eV for the valence-Band States Γ_4( z ), Γ_5( x ), and Γ_5( y ), respectively. Results from PC spectroscopy revealed the crystal-field and spin–orbit splitting were 3.5 meV and 39.9 meV. The gradual decrease of PC intensity with decreasing temperature can be explained on the basis of trapping centers associated with native defects in the MnAl_2S_4 layers. Plots of log J _ph, the PC current density, against 1/ T , revealed a dominant trap level in the high-temperature region. By comparing PC and the Hall effect results, we confirmed that this trap level is a shallow donor 18.9 meV below the Conduction Band.

  • Photocurrent Spectroscopic Study of Temperature-Dependent Photoresponse and Valence-Band Splitting in MnAl2S4 Layers
    Journal of Electronic Materials, 2014
    Co-Authors: K. J. Hong, T. S. Jeong, C. J. Youn
    Abstract:

    The temperature-dependent photoresponse characteristics of MnAl2S4 layers have been investigated, for the first time, by use of photocurrent (PC) spectroscopy. Three peaks were observed at all temperatures. The electronic origin of these peaks was associated with Band-to-Band transitions from the valence-Band States Γ4(z), Γ5(x), and Γ5(y) to the Conduction-Band State Γ1(s). On the basis of the relationship between PC-peak energy and temperature, the optical Band gap could be well expressed by the expression E g(T) = E g(0) − 2.80 × 10−4 T 2/(287 + T), where E g(0) was estimated to be 3.7920 eV, 3.7955 eV, and 3.8354 eV for the valence-Band States Γ4(z), Γ5(x), and Γ5(y), respectively. Results from PC spectroscopy revealed the crystal-field and spin–orbit splitting were 3.5 meV and 39.9 meV. The gradual decrease of PC intensity with decreasing temperature can be explained on the basis of trapping centers associated with native defects in the MnAl2S4 layers. Plots of log J ph, the PC current density, against 1/T, revealed a dominant trap level in the high-temperature region. By comparing PC and the Hall effect results, we confirmed that this trap level is a shallow donor 18.9 meV below the Conduction Band.

Ying-sheng Huang - One of the best experts on this subject based on the ideXlab platform.

  • Temperature dependent photoreflectance and photoluminescence characterization of GaInNAs∕GaAs single quantum well structures
    Journal of Applied Physics, 2004
    Co-Authors: T. H. Chen, Ying-sheng Huang, Der Yuh Lin, Kwong-kau Tiong
    Abstract:

    Ga0.69In0.31NxAs1−x∕GaAs single quantum well (SQW) structures with three different nitrogen compositions ( x=0%, 0.6%, and 0.9%) have been characterized, as functions of temperature in the range 10–300K, by the techniques of photoreflectance (PR) and photoluminescence (PL). In PR spectra, clear Franz-Keldysh oscillations (FKOs) above the GaAs Band edge and the various excitonic transitions originating from the QW region have been observed. The built-in electric field in the SQW has been determined from FKOs and found to increase with N concentration. The PR signal has been found to decrease for nitrogen incorporated samples when the temperature was lowered due to a weakening of the modulation efficiency induced by carrier localization. A careful analysis of PR and PL spectra has led to the identification of various excitonic transitions, mnH(L), between the mth Conduction Band State and the nth heavy (light)-hole Band State. The anomalous temperature dependent 11H transition energy and linewidth observed ...

  • Structural and Optical Studies of ZnCdSe/ZnSe/ZnMgSSe Separate Confinement Heterostructures with Different Buffer Layers
    Japanese Journal of Applied Physics, 1998
    Co-Authors: Ying-sheng Huang, Giin–sang Chen, Shu Tsun Chou
    Abstract:

    Detailed structural and optical studies of ZnCdSe/ZnSe/ZnMgSSe separate confinement heterostructures (SCH) grown on ZnSe, ZnSe/ZnSSe strained-layer superlattices (SLS), and GaAs buffer layers at the II–VI/GaAs interface have been carried out by employing transmission electron microscopy, variable temperature photoluminescence (PL), and contactless electroreflectance (CER) measurements. A significant improvement on the defect reduction and the optical quality has been observed by using either the ZnSe/ZnSSe SLS or GaAs as the buffer layers when compared to that of the sample using only ZnSe as the buffer layer. However, the sample grown with the SLS buffer layers reveals a room temperature PL intensity higher than that of the sample grown with a GaAs buffer layer, which may still suffer from the great ionic differences between the II–V and III–V atoms. Using 15 K CER spectra, we have also studied various excitonic transitions originating from strained Zn0.80Cd0.20Se/ZnSe single quantum well in SCH with different buffer layers. An analysis of the CER spectra has led to the identification of various excitonic transitions, mnH (L), between the mth Conduction Band State and the nth heavy (light)-hole Band State. An excellent agreement between experiments and theoretical calculations based on the envelope function approximation model has been achieved.

  • Contactless electroreflectance study of strained Zn0.79Cd0.21Se/ZnSe double quantum wells
    Journal of Applied Physics, 1998
    Co-Authors: Der-yuh Lin, Ying-sheng Huang, W. H. Lan, Shoou-jinn Chang, S. C. Chou, Wu-ching Chou
    Abstract:

    We have studied various excitonic transitions of strained Zn0.79Cd0.21Se/ZnSe double quantum wells, grown by molecular beam epitaxy on (100) GaAs substrates, using contactless electroreflectance (CER) at 15 and 300 K. A number of intersub-Band transitions in the CER spectra from the sample have been observed. An analysis of the CER spectra has led to the identification of various excitonic transitions, mnH(L), between the mth Conduction Band State and the nth heavy (light)-hole Band State. The Conduction-Band offset Qc is used as an adjustable parameter to study the Band offset in the strained Zn0.79Cd0.21Se/ZnSe system. The value of Qc is determined to be 0.67±0.03.

  • Temperature dependence of quantized States in an InGaAs/GaAs strained asymmetric triangular quantum well
    Semiconductor Science and Technology, 1996
    Co-Authors: W. S. Chi, Der-yuh Lin, Ying-sheng Huang, H. Qiang, Fred H. Pollak, D.l. Mathine, George N. Maracas
    Abstract:

    Photoreflectance (PR), contactless electroreflectance (CER) and piezoreflectance (PzR) measurements of an InGaAs/GaAs strained asymmetric triangular quantum well (ATQW) heterostructure as a function of temperature in the range of 20 to 300 K have been carried out. The structure was fabricated by molecular beam epitaxy using the digital alloy compositional grading method. A careful analysis of the PR, CER and PzR spectra has led to the identification of various excitonic transitions, mnH(L), between the mth Conduction Band State to the nth heavy(light)-hole Band State. Comparison of the observed intersubBand transitions with a theoretical calculation based on the envelope function model, including the effects of strain, provide a self-consistent check of the ATQW composition profile. The detailed study of the temperature dependence of the excitonic transition energies indicates that the potential profile of the ATQW varies at different temperatures. The parameters that describe the temperature dependence of are evaluated. The anomalous behaviour of the temperature dependence of the linewidth of 11H, , is compared with recent results for GaAs/AlGaAs and InGaAs/GaAs symmetric rectangular quantum wells of comparable dimensions.

  • Modulation spectroscopy study of an InGaAs/GaAs-strained asymmetric triangular quantum well heterostructure
    Il Nuovo Cimento D, 1995
    Co-Authors: Ying-sheng Huang, W. S. Chi, H. Qiang, Fred H. Pollak, D.l. Mathine, George N. Maracas
    Abstract:

    We have studied modulation spectra related to the intersubBand transitions at 300 K and 20 K from an In GaAs/GaAs-strained asymmetric triangular quantum well (ATQW) heterostructures fabricated by molecular beam epitaxy using the digital alloy compositional grading (DACG) method. A careful analysis of the spectra has led to the identification of various excitonic transitions,mnh(1), between them-th Conduction Band State to then-th, heavy (light)-hole Band State. Comparison of the observed intersubBand transitions with a theoretical calculation based on the envelope, function model, including the effects of strain provided a self-consistent verification that the DACG method produced the intended ATQW composition profile.

Kwong-kau Tiong - One of the best experts on this subject based on the ideXlab platform.

  • Temperature dependent photoreflectance and photoluminescence characterization of GaInNAs∕GaAs single quantum well structures
    Journal of Applied Physics, 2004
    Co-Authors: T. H. Chen, Ying-sheng Huang, Der Yuh Lin, Kwong-kau Tiong
    Abstract:

    Ga0.69In0.31NxAs1−x∕GaAs single quantum well (SQW) structures with three different nitrogen compositions ( x=0%, 0.6%, and 0.9%) have been characterized, as functions of temperature in the range 10–300K, by the techniques of photoreflectance (PR) and photoluminescence (PL). In PR spectra, clear Franz-Keldysh oscillations (FKOs) above the GaAs Band edge and the various excitonic transitions originating from the QW region have been observed. The built-in electric field in the SQW has been determined from FKOs and found to increase with N concentration. The PR signal has been found to decrease for nitrogen incorporated samples when the temperature was lowered due to a weakening of the modulation efficiency induced by carrier localization. A careful analysis of PR and PL spectra has led to the identification of various excitonic transitions, mnH(L), between the mth Conduction Band State and the nth heavy (light)-hole Band State. The anomalous temperature dependent 11H transition energy and linewidth observed ...

  • Temperature dependence of quantized States in an In0.86Ga0.14As0.3P0.7/InP quantum well heterostructure
    Journal of Applied Physics, 1997
    Co-Authors: Dabin Lin, Yen-ru Huang, Yihang Chen, Kwong-kau Tiong
    Abstract:

    Piezoreflectance (PzR) and contactless electroreflectance (CER) measurements of an In0.86Ga0.14As0.3P0.7/InP quantum well heterostructure as a function of temperature in the range of 20–300 K have been carried out. A careful analysis of the PzR and CER spectra has led to the identification of various excitonic transitions, mnH(L), between the mth Conduction Band State and the nth heavy (light)-hole Band State. The parameters that describe the temperature dependence of EmnH(L) are evaluated. A detailed study of the temperature variation of excitonic transition energies indicates that the main influence of temperature on quantized transitions is through the temperature dependence of the Band gap of the constituent material in the well. The temperature dependence of the linewidth of 11H exciton is evaluated and compared with that of the bulk material.