The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform

Alireza Nojeh - One of the best experts on this subject based on the ideXlab platform.

  • stabilization of laser induced thermionic electron emission from carbon nanotubes through rapid power switching
    International Vacuum Nanoelectronics Conference, 2014
    Co-Authors: Mike Chang, Mehran Vahdani Moghaddam, Alireza Nojeh
    Abstract:

    The electron emission stability of a carbon nanotube-based optically-activated cathode is investigated. The emission mechanism is thermionic, based on localized light-induced Heating of the carbon nanotube forest - the Heat Trap effect. We demonstrate stabilized emission behavior by introducing a switching phase in the input optical power. This effectively eliminates or significantly reduces the decay in emission current with time.

  • solar electron source and thermionic solar cell
    AIP Advances, 2012
    Co-Authors: Parham Yaghoobi, Mehran Vahdani Moghaddam, Alireza Nojeh
    Abstract:

    Common solar technologies are either photovoltaic/thermophotovoltaic, or use indirect methods of electricity generation such as boiling water for a steam turbine. Thermionic energy conversion based on the emission of electrons from a hot cathode into vacuum and their collection by an anode is also a promising route. However, thermionic solar conversion is extremely challenging as the sunlight intensity is too low for Heating a conventional cathode to thermionic emission temperatures in a practical manner. Therefore, compared to other technologies, little has been done in this area, and the devices have been mainly limited to large experimental apparatus investigated for space power applications. Based on a recently observed “Heat Trap” effect in carbon nanotube arrays, allowing their efficient Heating with low-power light, we report the first compact thermionic solar cell. Even using a simple off-the-shelf focusing lens, the device delivered over 1 V across a load. The device also shows intrinsic storage capacity.

  • Heat Trap light induced localized Heating and thermionic electron emission from carbon nanotube arrays
    Solid State Communications, 2011
    Co-Authors: Parham Yaghoobi, Mehran Vahdani Moghaddam, Alireza Nojeh
    Abstract:

    Abstract Light-induced Heating of a typical bulk conductor to thermionic electron emission temperatures usually requires high-power lasers. This is because of the efficient dissipation of Heat generated at the illuminated spot to the surroundings, since electrical conductors are normally also good thermal conductors. We show that the situation can be drastically different in a carbon nanotube forest and a spot on the surface of the forest can be Heated to above 2000 K using a low-power beam of visible light, leading to localized thermionic electron emission. This unique phenomenon may be explained by a rapid drop in thermal conductivity with increase in temperature, leading to a positive feedback that thermally isolates an island on the forest. Applications include thermoelectrics, photocathodes, optical switches, solar cells and even solar displays.

Parham Yaghoobi - One of the best experts on this subject based on the ideXlab platform.

  • solar electron source and thermionic solar cell
    AIP Advances, 2012
    Co-Authors: Parham Yaghoobi, Mehran Vahdani Moghaddam, Alireza Nojeh
    Abstract:

    Common solar technologies are either photovoltaic/thermophotovoltaic, or use indirect methods of electricity generation such as boiling water for a steam turbine. Thermionic energy conversion based on the emission of electrons from a hot cathode into vacuum and their collection by an anode is also a promising route. However, thermionic solar conversion is extremely challenging as the sunlight intensity is too low for Heating a conventional cathode to thermionic emission temperatures in a practical manner. Therefore, compared to other technologies, little has been done in this area, and the devices have been mainly limited to large experimental apparatus investigated for space power applications. Based on a recently observed “Heat Trap” effect in carbon nanotube arrays, allowing their efficient Heating with low-power light, we report the first compact thermionic solar cell. Even using a simple off-the-shelf focusing lens, the device delivered over 1 V across a load. The device also shows intrinsic storage capacity.

  • Heat Trap light induced localized Heating and thermionic electron emission from carbon nanotube arrays
    Solid State Communications, 2011
    Co-Authors: Parham Yaghoobi, Mehran Vahdani Moghaddam, Alireza Nojeh
    Abstract:

    Abstract Light-induced Heating of a typical bulk conductor to thermionic electron emission temperatures usually requires high-power lasers. This is because of the efficient dissipation of Heat generated at the illuminated spot to the surroundings, since electrical conductors are normally also good thermal conductors. We show that the situation can be drastically different in a carbon nanotube forest and a spot on the surface of the forest can be Heated to above 2000 K using a low-power beam of visible light, leading to localized thermionic electron emission. This unique phenomenon may be explained by a rapid drop in thermal conductivity with increase in temperature, leading to a positive feedback that thermally isolates an island on the forest. Applications include thermoelectrics, photocathodes, optical switches, solar cells and even solar displays.

Mehran Vahdani Moghaddam - One of the best experts on this subject based on the ideXlab platform.

  • stabilization of laser induced thermionic electron emission from carbon nanotubes through rapid power switching
    International Vacuum Nanoelectronics Conference, 2014
    Co-Authors: Mike Chang, Mehran Vahdani Moghaddam, Alireza Nojeh
    Abstract:

    The electron emission stability of a carbon nanotube-based optically-activated cathode is investigated. The emission mechanism is thermionic, based on localized light-induced Heating of the carbon nanotube forest - the Heat Trap effect. We demonstrate stabilized emission behavior by introducing a switching phase in the input optical power. This effectively eliminates or significantly reduces the decay in emission current with time.

  • solar electron source and thermionic solar cell
    AIP Advances, 2012
    Co-Authors: Parham Yaghoobi, Mehran Vahdani Moghaddam, Alireza Nojeh
    Abstract:

    Common solar technologies are either photovoltaic/thermophotovoltaic, or use indirect methods of electricity generation such as boiling water for a steam turbine. Thermionic energy conversion based on the emission of electrons from a hot cathode into vacuum and their collection by an anode is also a promising route. However, thermionic solar conversion is extremely challenging as the sunlight intensity is too low for Heating a conventional cathode to thermionic emission temperatures in a practical manner. Therefore, compared to other technologies, little has been done in this area, and the devices have been mainly limited to large experimental apparatus investigated for space power applications. Based on a recently observed “Heat Trap” effect in carbon nanotube arrays, allowing their efficient Heating with low-power light, we report the first compact thermionic solar cell. Even using a simple off-the-shelf focusing lens, the device delivered over 1 V across a load. The device also shows intrinsic storage capacity.

  • Heat Trap light induced localized Heating and thermionic electron emission from carbon nanotube arrays
    Solid State Communications, 2011
    Co-Authors: Parham Yaghoobi, Mehran Vahdani Moghaddam, Alireza Nojeh
    Abstract:

    Abstract Light-induced Heating of a typical bulk conductor to thermionic electron emission temperatures usually requires high-power lasers. This is because of the efficient dissipation of Heat generated at the illuminated spot to the surroundings, since electrical conductors are normally also good thermal conductors. We show that the situation can be drastically different in a carbon nanotube forest and a spot on the surface of the forest can be Heated to above 2000 K using a low-power beam of visible light, leading to localized thermionic electron emission. This unique phenomenon may be explained by a rapid drop in thermal conductivity with increase in temperature, leading to a positive feedback that thermally isolates an island on the forest. Applications include thermoelectrics, photocathodes, optical switches, solar cells and even solar displays.

William Selde - One of the best experts on this subject based on the ideXlab platform.

Ramsey Tate - One of the best experts on this subject based on the ideXlab platform.