Growth and fabrication of Au-catalyzed GaAs nanowire solar cells on Si substrates

• Main Authors: Jian, Ke-Ren, 簡克任
• Other Authors: Huang, Jin-Hua
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/12697817149602857973

碩士 === 國立清華大學 === 材料科學工程學系 === 100 === In comparison with silicon solar cells, the GaAs cells offer the advantage of having high absorption coefficient and direct bandgap. In particular, the GaAs cells in the form of coaxial nanowires offer the further advantage of having optimal light absorption and enhanced carrier collection, and thus have great potential to implement advanced high efficiency schemes. Synthesis and fabrication of GaAs nanowire solar cells on GaAs substrates has been widely investigated. However, epitaxial growth of GaAs nanowires on Si substrates has been rarely reported. In this work, we report the realization of GaAs nanowire solar cells on Si substrates. Synthesis of p-n coaxial GaAs nanowires was achieved by means of the Au-catalyzed vapour-liquid-solid (VLS) method by MBE using Be and Si as the p-type and n-type dopants, respectively. In device process, photoresist was first spin coated on the nanowire sample, followed by oxygen plasma etch to remove the photoresist from the tip of the nanowires. Indium tin oxide was then deposited on top of the nanowires by e-beam evaporation and annealed for 10 min to form transparent contact to the sample surface. Morphology of the devices was analyzed by scanning electron microscopy and I-V characteristics were measured using a solar simulation system. The results reveal a good progress for the use of GaAs nanowires in the fabrication of third generation solar cells on Si substrates.