Title :
Optimization of Growth of GaInNAs Dilute Nitrides for Multi-junction Solar Cell Applications
Author :
Shimizu, Yukiko ; Miyashita, Naoya ; Mura, Yusuke ; Uedono, Akira ; Okada, Yoshitaka
Author_Institution :
Inst. of Appl. Phys., Tsukuba Univ., Ibaraki
Abstract :
We have investigated the effect of growth temperature on the final crystal quality of GaInNAs solar cells in atomic hydrogen-assisted molecular beam epitaxy (H-MBE). A higher growth temperature of ~500degC has been found to be the optimum and resulted in both improved crystal quality and solar cell performance. The photoluminescence (PL) peak intensity was one order of magnitude stronger and the electron mobility of 250 cm2/Vs was 30 % higher for GaInNAs films grown at Tsub=520degC than at the more conventional growth temperature of 480degC. We have also investigated the vacancy-type defects in Ga(In)NAs films and found that the defect concentrations were as low as a LEC-GaAs substrate. Our unoptimized p-GaAs/i-n-GaInNAs heterojunction solar cell showed a maximum quantum efficiency of ~50 % and a low diode factor of 1.4
Keywords :
III-V semiconductors; electron mobility; gallium arsenide; gallium compounds; indium compounds; molecular beam epitaxial growth; optimisation; photoluminescence; semiconductor epitaxial layers; semiconductor growth; semiconductor heterojunctions; solar cells; vacancies (crystal); 480 C; 500 C; GaAs-GaInNAs; MBE; atomic hydrogen-assisted molecular beam epitaxy; defect concentrations; dilute nitrides; diode factor; electron mobility; multijunction solar cell; optimization; photoluminescence peak intensity; quantum efficiency; semiconductor heterojunction; thin films; vacancy-type defects; Atomic beams; Atomic layer deposition; Diodes; Electron mobility; Heterojunctions; Molecular beam epitaxial growth; Photoluminescence; Photovoltaic cells; Substrates; Temperature; Dilute nitrides; Multi junction solar cell; RF-MBE;
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.2006.279580
