Abstract
Higher-efficiency solar cells improve the likelihood that concentrator photovoltaic systems will become cost effective. A four-junction GaAs- and Ge-based solar cell incorporating a 1-eV bandgap material has an ideal AM0 efficiency of~40% and could also be used in a terrestrial concentrator module. The dilute-N GaAsN alloy's bandgap can be reduced to near 1 eV when the nitrogen content is 2% -3%. Indium can also be added to the alloy to improve lattice matching to GaAs and Ge. We have used deep-level transient spectroscopy (DLTS) to characterize traps in both p-type and n-type GaAsN. For each type of material, the dominant DLTS signal corresponds to an electron trap having an activation energy of about 0.35 eV for p-type GaAsN and about 0.45 eV for n-type GaAsN. In both types ofmaterials, the trap concentrations, modified by ..lambda..-effect factors, increase with both increasing N content and increased doping.
Original language | American English |
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Number of pages | 5 |
State | Published - 2005 |
Event | 2005 DOE Solar Energy Technologies Program Review Meeting - Denver, Colorado Duration: 7 Nov 2005 → 10 Nov 2005 |
Conference
Conference | 2005 DOE Solar Energy Technologies Program Review Meeting |
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City | Denver, Colorado |
Period | 7/11/05 → 10/11/05 |
Bibliographical note
Presented at the 2005 DOE Solar Energy Technologies Program Review Meeting held November 7-10, 2005 in Denver, Colorado. Also included in the proceedings available on CD-ROM (DOE/GO-102006-2245; NREL/CD-520-38557)NREL Publication Number
- NREL/CP-520-38916
Keywords
- GaAsN
- NREL
- photovoltaics (PV)
- PV
- solar
- transient spectroscopy