Recent progress in InGaAsSb/GaSb TPV devices
- AstroPower, Inc., Newark, DE (United States)
- Lockheed Martin Corp., Schenectady, NY (United States)
AstroPower is developing InGaAsSb thermophotovoltaic (TPV) devices. This photovoltaic cell is a two-layer epitaxial InGaAsSb structure formed by liquid-phase epitaxy on a GaSb substrate. The (direct) bandgap of the In{sub 1{minus}x}Ga{sub x}As{sub 1{minus}y}Sb{sub y} alloy is 0.50 to 0.55 eV, depending on its exact alloy composition (x,y); and is closely lattice-matched to the GaSb substrate. The use of the quaternary alloy, as opposed to a ternary alloy--such as, for example InGaAs/InP--permits low bandgap devices optimized for 1,000 to 1,500 C thermal sources with, at the same time, near-exact lattice matching to the GaSb substrate. Lattice matching is important since even a small degree of lattice mismatch degrades device performance and reliability and increases processing complexity. Internal quantum efficiencies as high as 95% have been measured at a wavelength of 2 microns. At 1 micron wavelengths, internal quantum efficiencies of 55% have been observed. The open-circuit voltage at currents of 0.3 A/cm{sup 2} is 0.220 volts and 0.280 V for current densities of 2 A/cm{sup 2}. Fill factors of 56% have been measured at 60 mA/cm{sup 2}. However, as current density increases there is some decrease in fill factor. The results to date show that the GaSb-based quaternary compounds provide a viable and high performance energy conversion solution for thermophotovoltaic systems operating with 1,000 to 1,500 C source temperatures.
- Research Organization:
- Knolls Atomic Power Lab. (KAPL), Niskayuna, NY (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Nuclear Energy, Washington, DC (United States)
- DOE Contract Number:
- AC12-76SN00052
- OSTI ID:
- 296773
- Report Number(s):
- KAPL-P-000047; CONF-9605348-; ON: DE99000437; TRN: AHC29903%%171
- Resource Relation:
- Conference: 25. IEEE photovoltaic specialists conference, Washington, DC (United States), 13-17 May 1996; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Quaternary InGaAsSb Thermophotovoltaic Diode Technology
InGaAsSb thermophotovoltaic diode physics evaluation