Effect of substrate off-orientation on the characteristics of GaInP/AlGaInP single heterojunction solar cells

• Published in: The Korean journal of chemical engineering Vol. 36; no. 2; pp. 305 - 311
• Main Authors: Kim, Junghwan, Shin, Hyun-Beom
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.02.2019; Springer Nature B.V; 한국화학공학회
• Subjects: Aluminum gallium indium phosphides; Biotechnology; Buffer layers; Catalysis; Chemistry; Chemistry and Materials Science; Circuits; Current density; Current voltage characteristics; Electronic; Gallium arsenide; Gallium indium phosphide; Heterojunctions; Industrial Chemistry/Chemical Engineering; Inorganic; Materials (Organic; Materials Science; Morphology; Orientation effects; Photovoltaic cells; Secondary ion mass spectrometry; Short circuit currents; Solar cells; Substrates; Thin Films; 화학공학; Impurity Incorporation; Heterojunction Solar Cell; GaInP/AlGaInP; Substrate Off-orientation
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-018-0195-5

The effects of GaAs substrate off-orientation on GaInP/AlGaInP heterojunction solar cells were investigated. The performances of solar cells fabricated on 2° and 10° off GaAs substrates were compared. The short circuit current densities were 10.44 mA/cm 2 for the 10° off sample, 7.15 mA/cm 2 and 7.41 mA/cm 2 for the 2° off samples, which showed 30% higher short-circuit current density for 10° off samples. Also, 30% higher external quantum efficiencies and smooth surface morphology were observed in the solar cell fabricated on the 10° off GaAs substrate. Secondary ion mass spectrometry depth profiles showed that the solar cells on 2° off substrates had a 20-times higher oxygen concentration than the solar cells on 10° off GaAs substrate in the n-GaAs/GaAs buffer layer. The 30% reduction for the solar cells on 2° substrates in short circuit current density (J sc ) was attributed to the higher oxygen concentration of the 2° off samples than the 10° off samples. I-V characteristics comparison between different front contact grid patterns was also performed for optimization of grid contacts. A 0.47 V bandgap-voltage offset, one of the device performance figures of merit to compare PV cells with different materials, was obtained.