Title :
Lattice-Mismatched InGaAsP and AlGaInAs Quaternary Materials for Thermophotovoltaic Applications
Author :
Newman, Frederick D. ; Varghese, Tansen ; Aeby, Ian ; Sandoval, Annette C. ; Turner, Michele V. ; Endicter, Scott P. ; Girard, Gerald ; Fiedor, Joseph N. ; Siergiej, Richard R. ; Wernsman, Bernard ; Wehrer, Rebecca J. ; Maranchi, Jeff P.
Author_Institution :
EMCORE Photovoltaics, Albuquerque, NM
Abstract :
Experimental results are presented for lattice-mismatched (LMM) In 0.8Ga0.2As0.76P0.24 and Al 0.07Ga0.255In0.675As quaternary materials used in thermophotovoltaic (TPV) devices. Epistructures were grown on 3-inch diameter InP substrates by metalorganic vapor phase epitaxy (MOVPE) and processed as monolithically interconnected modules (MIMs) using conventional photolithography and chemical wet etching. Electrical characterization of single-bandgap quaternary devices revealed that the two have roughly equivalent electrical performance. Comparable X-ray diffraction data, high voltage factors and fill factors indicate the materials are of high crystalline and electrical quality, and perform comparably to expectations set by long experience with 0.6 eV lattice-mismatched InGaAs devices of similar device design. Integration of the high and low bandgaps into tandem devices has proven problematic, however, suggesting unresolved materials and processing issues
Keywords :
III-V semiconductors; MOCVD; aluminium compounds; etching; gallium arsenide; gallium compounds; indium compounds; photolithography; semiconductor epitaxial layers; semiconductor growth; solar cells; vapour phase epitaxial growth; Al0.07Ga0.255In0.675As; In0.8Ga0.2As0.76P0.24; InP; MOVPE; X-ray diffraction; chemical wet etching; conventional photolithography; electrical characterization; epistructures; lattice-mismatched devices; lattice-mismatched quaternary materials; low bandgaps; metalorganic vapor phase epitaxy; monolithically interconnected modules; semiconductor substrates; single-bandgap quaternary devices; tandem devices; thermophotovoltaic devices; Chemical processes; Crystalline materials; Epitaxial growth; Epitaxial layers; Indium phosphide; Lithography; Substrates; Voltage; Wet etching; X-ray diffraction;
Conference_Titel :
Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
1-4244-0017-1
Electronic_ISBN :
1-4244-0017-1
DOI :
10.1109/WCPEC.2006.279541
