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This paper presents two of our recent developments in the area of III–V ternary and quaternary materials growth technology for high efficiency thermophotovoltaic (TPV) cells. It is well recognized that growth of TPV cell materials from melts or solutions presents the most economical option. We have investigated bulk substrate growth from melt as well as epitaxial growth from liquid phase. In the bulk crystal growth area, we have been concentrating on the growth of 50 mm or larger diameter device quality ternary III–V substrates. In the epitaxial growth arena, we have developed a new thermochemistry for growing ternary and quaternary compounds on binary substrates from quaternary solutions. Some of the recent results pertaining to the bulk growth of GaInSb and epitaxial growth of GaInAs, InAsSb and GaInAsSb on GaAs substrates will be discussed here. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper presents results of experimental and theoretical research on antimonide- based thermophotovoltaic (TPV) materials and cells. The topics discussed include: growth of large diameter ternary GalnSb bulk crystals, substrate preparation, diffused junction processes, cell fabrication and characterization, and, cell modeling. Ternary GalnSb boules up to 2 inches in diameter have been grown using the vertical Bridgman technique with a novel self solute feeding technique. A single step diffusion process followed by precise etching of the diffused layer has been developed to obtain a diffusion profile appropriate for high efficiency, p-n junction GaSb and GalnSb thermophotovoltaic cells. The optimum junction depth to obtain the highest quantum efficiency and open circuit voltage has been identified based on diffusion lengths (or minority carrier lifetimes), carrier mobility and experimental diffused impurity profiles. Theoretical assessment of the performance of ternary (GalnSb) and binary (GaSh) cells fabricated by Zn diffusion in bulk substrates has been performed using PC-1D one-dimensional computer simulations. Several factors affecting the ceil performances such as the effects of emitter doping profile, emitter thickness and recombination mechanisms (Auger, radiative and Shocldey-Read-Hall), the advantages of surface passivation and the impact of dark current due to the metallic grid will be discussed. The conditions needed for diffused junction cells on ternary and binary substrates to achieve similar performance to the epitaxially grown lattice- matched quaternary cells are identified. [ABSTRACT FROM AUTHOR]

This paper assesses the performance of antimonide-based thermophotovoltaic cells fabricated by different technologies. In particular, the paper compares the performance of lattice matched quaternary (GalnAsSb) ceils epitaxially grown on GaSb substrates to the performance of ternary (GalnSb) and binary (GaSb) cells fabricated by Zn diffusion on bulk substrates. The focus of the paper is to delineate the key performance advantages of the highest performance-to-date of the quaternary cells to the performance of the alternative ternary and binary antimonide-based diffusion technology. The performance characteristics of the cells considered are obtained from PC-ID simulations using appropriate material parameters. [ABSTRACT FROM AUTHOR]