Band structure control of multi-band gap semiconductors and its application to solar cell

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04956
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 30010:Crystal engineering-related
• Research Institution: University of Yamanashi
• Principal Investigator: NABETANI Yoichi 山梨大学, 大学院総合研究部, 教授 (30283196)
• Co-Investigator(Kenkyū-buntansha): 松本 俊 山梨大学, 大学院総合研究部, 教授 (00020503) ; 村中 司 山梨大学, 大学院総合研究部, 准教授 (20374788)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 太陽電池 / 格子歪

Outline of Final Research Achievements

In a multi-bandgap semiconductor having an intermediate band in the forbidden band, light can be absorbed through the intermediate band to generate free carriers. In this research, oxygen (O), which forms a localized level, is added to ZnTe to increase the density of the localized level and control the intermediate band.
ZnTeO alloy semiconductors were grown by molecular beam epitaxy, and its oxygen composition was analyzed by X-ray diffraction. We also revealed that oxygen forms a localized level in ZnTe by the photoluminescence method. Since ZnTe and ZnO, which form a ZnTeO alloy semiconductor, differ in interatomic distance by about 25%, strain occurs inside the crystal. The strain energy distribution was investigated by calculation at the atomic level.

Free Research Field

半導体結晶

Academic Significance and Societal Importance of the Research Achievements

太陽電池は燃料を必要とせず、太陽光を照射するだけで半永久的に利用できるため、身近な電力源としての役割は大きい。しかし現在実用化されているSi系やCuInGaSe(CIGS)系半導体太陽電池の効率は十数パーセントであり、さらなる高効率化は必須である。現在、高効率半導体は開発されているが、その製造方法やコストの問題から普及が困難であるが。本研究で提案する太陽電池は大量生産に適している。