GaSb thermophotovoltaic cells grown on GaAs by molecular beam epitaxy using interfacial misfit arrays

Abstract

There exists a long-term need for foreign substrates on which to grow GaSb-based optoelectronic devices. We address this need by using interfacial misfit arrays to grow GaSb-based thermophotovoltaic cells directly on GaAs (001) substrates and demonstrate promising performance. We compare these cells to control devices grown on GaSb substrates to assess device properties and material quality. The room temperature dark current densities show similar characteristics for both cells on GaAs and on GaSb. Under solar simulation the cells on GaAs exhibit an open-circuit voltage of 0.121 V and a short-circuit current density of 15.5 mA/cm2. In addition, the cells on GaAs substrates maintain 10% difference in spectral response to those of the control cells over a large range of wavelengths. While the cells on GaSb substrates in general offer better performance than the cells on GaAs substrates, the cost-savings and scalability offered by GaAs substrates could potentially outweigh the reduction in performance. By further optimizing GaSb buffer growth on GaAs substrates, Sb-based compound semiconductors grown on GaAs substrates with similar performance to devices grown directly on GaSb substrates could be realized.

Electrochemical Liquid-Liquid-Solid Deposition of Crystalline Gallium Antimonide

“…Gallium antimonide (GaSb) thin films are attractive platforms for energy conversion technologies. For example, crystalline films of GaSb function as the absorber layers and /or substrate in the most efficient thermophotovoltaics [1][2][3], as deposition substrates for lattice matched ternary (AlGaSb, InAsSb) and quaternary (AlGaAsSb, InGaAsSb) alloys [4,5], as infrared-capturing cells in tandem solar cells [6] and as the lasing medium in low voltage diode lasers [7]. Unfortunately, the current methods (e.g.…”

Solid solution strengthening in GaSb/GaAs: A mode to reduce the TD density through Be-doping

“…[1][2][3][4][5][6] Although it could be expected to obtain only the 90 MDs due to their energetically favourable state with respect to the 60 ones, both types are usually observed in this system at similar growth conditions. [7][8][9] The 60 MDs generate threading dislocations (TDs), which emerging from the interface glide to the surface resulting in material degradation, decrementing its electrical and optical properties.…”

Effects of the composition of diffusion source on the surface concentration and effective surface diffusivity of Zn in n-GaSb

“…With a bandgap of 0.72 eV at room temperature, GaSb is a promising material for fabricating optoelectronic and electronic devices with a response spectrum in the near infrared wavelength, such as lasers [1,2], photodiode [3,4], thermophotovoltaic cells [5,6], and so on. The key structure of these devices is the p-n junction, which can be fabricated by diffusing Zn into an n-GaSb substrate.…”