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Mircea Guina - One of the best experts on this subject based on the ideXlab platform.

  • Molecular Beam Epitaxy of Dilute Nitride Optoelectronic Devices
    Molecular Beam Epitaxy, 2018
    Co-Authors: Mircea Guina, Shu M. Wang, Arto Aho
    Abstract:

    Abstract Molecular beam epitaxy of Dilute Nitride materials has progressed a long way toward claiming its unique place as a technology that enables the development of new types of optoelectronics devices. This chapter starts by reviewing the particularities related to epitaxial incorporation of nitrogen into III–V materials using plasma-assisted molecular beam epitaxy. We then focus on describing the interplay between the growth parameters and nitrogen incorporation processes in Dilute Nitride arsenides (III-N-As). Emphasis is put on nitrogen-related growth kinetics that are accompanied by various bonding configurations and formation of several types of defects. Then we review the basics of MBE for Dilute Nitride antimonides (III-N-Sb) and Dilute Nitride phosphides (III-N-P). Finally, we review the growth optimization and properties of several classes of Dilute Nitride heterostructures for optoelectronics. These include uncooled long-wavelength laser diodes, ultrafast nonlinear devices, high power lasers enabling yellow-orange emission by frequency doubling, and high-efficiency multijunction solar cells, for which Dilute Nitride MBE technology is rapidly evolving and provides development opportunities.

  • performace of Dilute Nitride triple junction space solar cell grown by mbe
    E3S Web of Conferences, 2017
    Co-Authors: Arto Aho, Riku Isoaho, Antti Tukiainen, Ville Polojarvi, Marianna Raappana, Timo Aho, Mircea Guina
    Abstract:

    Dilute Nitride arsenide antimonide compounds offer widely tailorable band-gaps, ranging from 0.8 eV to 1.4 eV, for the development of lattice-matched multijunction solar cells with three or more junctions. Here we report on the performance of GaInP/GaAs/GaInNAsSb solar cell grown by molecular beam epitaxy. An efficiency of 27% under AM0 conditions is demonstrated. In addition, the cell was measured at different temperatures. The short circuit current density exhibited a temperature coefficient of 0.006 mA/cm 2 /°C while the corresponding slope for the open circuit voltage was −6.8 mV/°C. Further efficiency improvement, up to 32%, is projected by better current balancing and structural optimization.

  • OFC - Dilute Nitride SOAs for high-speed data processing in variable temperature conditions
    Optical Fiber Communication Conference, 2015
    Co-Authors: G. Giannoulis, Mircea Guina, V.-m. Korpijärvi, Nikolaos Iliadis, Jaakko Mäkelä, Jukka Viheriälä, Dimitris Apostolopoulos, Hercules Avramopoulos
    Abstract:

    We present the first experimental study of a Dilute Nitride SOA with high-speed gain dynamics and attractive thermal characteristics as a data processing element at 10Gb/s and at different operating temperatures.

  • Optical gain in 1.3-μm electrically driven Dilute Nitride VCSOAs
    Nanoscale Research Letters, 2014
    Co-Authors: Sefer Bora Lisesivdin, Mircea Guina, Naci Balkan, Ville-markus Korpijärvi, Nadir Ali Khan, Simone Mazzucato, Michael John Adams, Gabor Mezosi, Marc Sorel
    Abstract:

    We report the observation of room-temperature optical gain at 1.3 μm in electrically driven Dilute Nitride vertical cavity semiconductor optical amplifiers. The gain is calculated with respect to injected power for samples with and without a confinement aperture. At lower injected powers, a gain of almost 10 dB is observed in both samples. At injection powers over 5 nW, the gain is observed to decrease. For nearly all investigated power levels, the sample with confinement aperture gives slightly higher gain.

  • moth eye antireflection coatings fabricated by nanoimprint lithography on Dilute Nitride solar cell
    World Conference on Photovoltaic Energy Conversion, 2013
    Co-Authors: J Tommila, Arto Aho, Antti Tukiainen, Ville Polojarvi, Joel Salmi, Tapio Niemi, Mircea Guina
    Abstract:

    We report on the performance of biomimicked antireflection coating applied to Dilute Nitride solar cell. The coating consists of nanostructures replicating the moth-eye geometry and has been fabricated by nanoimprint lithography directly within the window layer covering the Dilute Nitride absorbing junction. The mean reflectivity within the spectral range of 320–1800 nm remains under 5% for incident angles up to 45°. The effect of the coating on the cell performance was assessed by measuring the current–voltage characteristics under simulated solar illumination. A clear performance increase was identified when comparing a solar cell with the moth-eye coating with a solar cell having a standard SiNx/SiO2 coating. Copyright © 2012 John Wiley & Sons, Ltd.

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

  • Influence of temperature on spin polarization dynamics in Dilute Nitride semiconductors—Role of nonparamagnetic centers
    Journal of Applied Physics, 2015
    Co-Authors: Michal Baranowski, J. Misiewicz
    Abstract:

    We report theoretical studies of spin polarization dynamics in Dilute Nitride semiconductors. We develop a commonly used rate equation model [Lagarde et al., Phys. Status Solidi A 204, 208 (2007) and Kunold et al. Phys. Rev. B 83, 165202 (2011)] to take into account the influence of shallow localizing states on the temperature dependence of spin polarization dynamics and a spin filtering effect. Presented investigations show that the experimentally observed temperature dependence of a spin polarization lifetime in Dilute Nitrides can be related to the electron capture process by shallow localizing states without paramagnetic properties. This process reduces the efficiency of spin filtering effect by deep paramagnetic centers, especially at low temperatures.

  • influence of temperature on spin polarization dynamics in Dilute Nitride semiconductors role of nonparamagnetic centers
    Journal of Applied Physics, 2015
    Co-Authors: Michal Baranowski, J. Misiewicz
    Abstract:

    We report theoretical studies of spin polarization dynamics in Dilute Nitride semiconductors. We develop a commonly used rate equation model [Lagarde et al., Phys. Status Solidi A 204, 208 (2007) and Kunold et al. Phys. Rev. B 83, 165202 (2011)] to take into account the influence of shallow localizing states on the temperature dependence of spin polarization dynamics and a spin filtering effect. Presented investigations show that the experimentally observed temperature dependence of a spin polarization lifetime in Dilute Nitrides can be related to the electron capture process by shallow localizing states without paramagnetic properties. This process reduces the efficiency of spin filtering effect by deep paramagnetic centers, especially at low temperatures.

  • on the oscillator strength in Dilute Nitride quantum wells on gaas
    Journal of Applied Physics, 2012
    Co-Authors: Krzysztof Ryczko, J. Misiewicz, Fabian Langer, Sven Höfling, G Sek, M. Kamp
    Abstract:

    We have investigated theoretically two kinds of Dilute-Nitride-based quantum well structures, InGaAsN/GaAs and InGaAsN/GaAsN/GaAs, both able to emit at 1.3 μm. The ground state transition energy and its oscillator strength have been probed as a function of the material composition in the single particle as well as the excitonic approximations. The modification of the bandgap energy due to nitrogen incorporation has been taken into account by using a two-level repulsion model. We have shown that in spite of a decrease of the electron-hole wave functions overlap with the mole fraction of nitrogen, the overall transition intensity of the excitonic transition can increase significantly due to the strongly composition dependent mass of the exciton. The latter makes Dilute Nitride quantum wells good candidates for the polaritonic physics and Bose-Einstein condensation of exciton polaritons at telecommunication wavelengths. We have also demonstrated that the exact values of the band offsets are necessary to be known as they have a critical impact on the actual transition oscillator strengths in these quantum wells.

  • On the oscillator strength in Dilute Nitride quantum wells on GaAs
    Journal of Applied Physics, 2012
    Co-Authors: Krzysztof Ryczko, G. Sęk, J. Misiewicz, Fabian Langer, Sven Höfling, M. Kamp
    Abstract:

    We have investigated theoretically two kinds of Dilute-Nitride-based quantum well structures, InGaAsN/GaAs and InGaAsN/GaAsN/GaAs, both able to emit at 1.3 μm. The ground state transition energy and its oscillator strength have been probed as a function of the material composition in the single particle as well as the excitonic approximations. The modification of the bandgap energy due to nitrogen incorporation has been taken into account by using a two-level repulsion model. We have shown that in spite of a decrease of the electron-hole wave functions overlap with the mole fraction of nitrogen, the overall transition intensity of the excitonic transition can increase significantly due to the strongly composition dependent mass of the exciton. The latter makes Dilute Nitride quantum wells good candidates for the polaritonic physics and Bose-Einstein condensation of exciton polaritons at telecommunication wavelengths. We have also demonstrated that the exact values of the band offsets are necessary to be k...

Luke J. Mawst - One of the best experts on this subject based on the ideXlab platform.

  • (Invited) Dilute-Nitride-Antimonide Materials Grown by MOVPE for Multi-Junction Solar Cell Application
    ECS Transactions, 2015
    Co-Authors: Luke J. Mawst, Zachary Lingley, Thomas F. Kuech, S. D. Lalumondiere
    Abstract:

    We have investigated the growth by metalorganic vapor phase epitaxy (MOVPE) of multinary (fourand fiveelement) DiluteNitride-antimonide materials on GaAs substrates. The lowest background carbon concentration (~ 5 × 10 cm) is observed in Dilute-Nitride materials grown at high temperature which do not contain Sb (i.e. InGaAsN). An increased depletion region width significantly improves the solar cell performance over that found from Dilute-Nitride cells grown at lower growth temperatures (~525C). The device performance of the single-junction solar cells with the low carbon background InGaAsN base region (InGaAsN/Ge double-junction solar cell) exhibit short-circuit current density, open-circuit voltage, fill factor, and efficiency values of 26.05 (28.46) mA/cm, 0.67 (0.9) V, 75.85 (72.8) %, and 13.2 (18.54) %, with anti-reflecting coating (ARC), respectively.

  • Time-resolved PL and TEM studies of MOVPE-grown bulk Dilute Nitride and bismide quantum well heterostructure
    Physics Simulation and Photonic Engineering of Photovoltaic Devices IV, 2015
    Co-Authors: Yongkun Sin, Zachary Lingley, Mark Peterson, Miles Brodie, Steven C. Moss, Tae-wan Kim, Honghyuk Kim, Yingxin Guan, Kamran Forghani, Luke J. Mawst
    Abstract:

    Among several approaches proposed to achieve high-efficiency III-V multi-junction solar cells, the most promising approach is to incorporate a bottom junction consisting of a 1 – 1.25 eV material. In particular, several research groups have studied MBE- and MOVPE-grown 1 – 1.25 eV bulk (In)GaAsN(Sb) Dilute Nitride lattice matched to GaAs substrates, but it is a challenge to grow Dilute Nitrides without introducing a number of localized states or defects. Localized states originating from random distributions of nitrogen sites in Dilute Nitrides behave as highly efficient traps, leading to short minority carrier lifetimes. As our group previously reported, carrier dynamics studies are indispensable in the optimization of Dilute Nitride materials growth to achieve improved solar cell performance. Also, bismide QW heterostructures have recently received a great deal of attention for applications in solar cells and semiconductor lasers because theoretical studies have predicted reduction in nonradiative recombination in Bicontaining materials. For the present study, we employed time-resolved photoluminescence (TR-PL) techniques to study carrier dynamics in MOVPE-grown bulk (In)GaAsN(Sb) materials nominally lattice matched to GaAs substrates. Compared to our previous samples, our present samples grown using different metalorganic precursors at higher growth temperatures showed a significantly less background C doping density. Carrier lifetimes were measured from such Dilute Nitride samples with low C doping density at various temperatures between 10K and RT. We also performed preliminary TR-PL measurements on MOVPE-grown bismide QW heterostructures at low temperatures. Carrier lifetimes were measured from as-grown and annealed bismide QW structures consisting of GaAsBi(P) wells and GaAsP barriers. Lastly, TEM cross sections were prepared from both Dilute Nitride and bismide samples for defect and composition analysis using a high resolution TEM.

  • properties of Dilute Nitride antimonide materials grown by metalorganic vapor phase epitaxy movpe for solar cell application
    Asia Communications and Photonics Conference 2013 (2013) paper AW4K.5, 2013
    Co-Authors: Luke J. Mawst, S. D. Lalumondiere, Thomas F. Kuech, Yongkun Sin, Tae-wan Kim, T Garrod, Kangho Kim, Jaejin Lee, William T Lotshaw, Steven C. Moss
    Abstract:

    Bulk Dilute-Nitride-antimonide materials are grown by MOVPE nominally lattice-matched to the GaAs substrate with bandgap energies in the 1-1.25eV range. Single-junction solar cells demonstrate a peak efficiency of 7.22% with high open circuit voltages (Voc=0.72V).

  • carrier dynamics in movpe grown bulk Dilute Nitride materials for multi junction solar cells
    Proceedings of SPIE, 2011
    Co-Authors: Yongkun Sin, S. D. Lalumondiere, Luke J. Mawst, Tae-wan Kim, T Garrod, William T Lotshaw, Jeremy Kirch, Steven C. Moss
    Abstract:

    Dilute Nitride materials with a 1eV band-gap lattice matched to GaAs substrates are attractive for high-efficiency multi-junction solar cells. Carrier lifetime measurements are crucial in optimizing material growth and p-i-n field-aided carrier-extraction-device design. One research group has reported carrier lifetimes of MBE-grown bulk InGaNAsSb materials, but there has been no report of carrier lifetime measurements from bulk InGaNAsSb grown by MOVPE. In this study, we report the growth of bulk InGaNAsSb by MOVPE and the first carrier lifetime measurement from MOVPE-grown bulk InGaNAsSb materials with E g = 1.0 - 1.2eV at 300K. We studied carrier dynamics in MOVPE-grown bulk Dilute Nitride materials nominally lattice matched to GaAs (100) substrates: 1μm thick In 0.035 GaN 0.025 As (E g = 1.0eV at 300K) and ~0.2μm thick In (0.05-0.07) GaN (0.01-0.02) AsSb (0.02-0.06) layers (E g = 1.2eV at 300K). Both structures are fully strained. The incorporation of N in InGaNAs leads to degradation in photoluminescence efficiency, but prior studies indicate the addition of Sb in MBE-grown InGaNAsSb improved the PL efficiency. Two-step post-growth thermal annealing processes were optimized to obtain maximum PL efficiencies that yielded a typical blue shift of 50 and 30meV for InGaNAs and InGaNAsSb, respectively. We employed a streak camera to measure carrier lifetimes from both as-grown and thermally annealed samples. Carrier lifetimes of <30psec were obtained from the InGaNAs samples, whereas carrier lifetimes of up to ~150psec were obtained from the InGaNAsSb samples. We discuss possible reasons for short carrier lifetimes measured from MOVPE-grown InGaNAs(Sb) materials.

  • Carrier dynamics in MOVPE-grown bulk Dilute Nitride materials for multi-junction solar cells
    Proceedings of SPIE, 2011
    Co-Authors: Yongkun Sin, S. D. Lalumondiere, Luke J. Mawst, Tae-wan Kim, T Garrod, William T Lotshaw, Jeremy Kirch, Steven C. Moss
    Abstract:

    Dilute Nitride materials with a 1eV band-gap lattice matched to GaAs substrates are attractive for high-efficiency multi-junction solar cells. Carrier lifetime measurements are crucial in optimizing material growth and p-i-n field-aided carrier-extraction-device design. One research group has reported carrier lifetimes of MBE-grown bulk InGaNAsSb materials, but there has been no report of carrier lifetime measurements from bulk InGaNAsSb grown by MOVPE. In this study, we report the growth of bulk InGaNAsSb by MOVPE and the first carrier lifetime measurement from MOVPE-grown bulk InGaNAsSb materials with E g = 1.0 - 1.2eV at 300K. We studied carrier dynamics in MOVPE-grown bulk Dilute Nitride materials nominally lattice matched to GaAs (100) substrates: 1μm thick In 0.035 GaN 0.025 As (E g = 1.0eV at 300K) and ~0.2μm thick In (0.05-0.07) GaN (0.01-0.02) AsSb (0.02-0.06) layers (E g = 1.2eV at 300K). Both structures are fully strained. The incorporation of N in InGaNAs leads to degradation in photoluminescence efficiency, but prior studies indicate the addition of Sb in MBE-grown InGaNAsSb improved the PL efficiency. Two-step post-growth thermal annealing processes were optimized to obtain maximum PL efficiencies that yielded a typical blue shift of 50 and 30meV for InGaNAs and InGaNAsSb, respectively. We employed a streak camera to measure carrier lifetimes from both as-grown and thermally annealed samples. Carrier lifetimes of

M. Kamp - One of the best experts on this subject based on the ideXlab platform.

  • on the oscillator strength in Dilute Nitride quantum wells on gaas
    Journal of Applied Physics, 2012
    Co-Authors: Krzysztof Ryczko, J. Misiewicz, Fabian Langer, Sven Höfling, G Sek, M. Kamp
    Abstract:

    We have investigated theoretically two kinds of Dilute-Nitride-based quantum well structures, InGaAsN/GaAs and InGaAsN/GaAsN/GaAs, both able to emit at 1.3 μm. The ground state transition energy and its oscillator strength have been probed as a function of the material composition in the single particle as well as the excitonic approximations. The modification of the bandgap energy due to nitrogen incorporation has been taken into account by using a two-level repulsion model. We have shown that in spite of a decrease of the electron-hole wave functions overlap with the mole fraction of nitrogen, the overall transition intensity of the excitonic transition can increase significantly due to the strongly composition dependent mass of the exciton. The latter makes Dilute Nitride quantum wells good candidates for the polaritonic physics and Bose-Einstein condensation of exciton polaritons at telecommunication wavelengths. We have also demonstrated that the exact values of the band offsets are necessary to be known as they have a critical impact on the actual transition oscillator strengths in these quantum wells.

  • On the oscillator strength in Dilute Nitride quantum wells on GaAs
    Journal of Applied Physics, 2012
    Co-Authors: Krzysztof Ryczko, G. Sęk, J. Misiewicz, Fabian Langer, Sven Höfling, M. Kamp
    Abstract:

    We have investigated theoretically two kinds of Dilute-Nitride-based quantum well structures, InGaAsN/GaAs and InGaAsN/GaAsN/GaAs, both able to emit at 1.3 μm. The ground state transition energy and its oscillator strength have been probed as a function of the material composition in the single particle as well as the excitonic approximations. The modification of the bandgap energy due to nitrogen incorporation has been taken into account by using a two-level repulsion model. We have shown that in spite of a decrease of the electron-hole wave functions overlap with the mole fraction of nitrogen, the overall transition intensity of the excitonic transition can increase significantly due to the strongly composition dependent mass of the exciton. The latter makes Dilute Nitride quantum wells good candidates for the polaritonic physics and Bose-Einstein condensation of exciton polaritons at telecommunication wavelengths. We have also demonstrated that the exact values of the band offsets are necessary to be k...

Michal Baranowski - One of the best experts on this subject based on the ideXlab platform.