Development of the very high efficiency thin-film multiple quantum well solar cells

2015 Fiscal Year Final Research Report

• Project/Area Number: 26630107
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Power engineering/Power conversion/Electric machinery
• Research Institution: The University of Tokyo
• Principal Investigator: Watanabe Kentaroh 東京大学, 先端科学技術研究センター, 特任講師 (30523815)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 半導体 / III-V族化合物 / 太陽電池 / 量子井戸 / 定量光学評価 / MOCVD / エピタキシャル成長

Outline of Final Research Achievements

In this research, we tried to fabricate the thin-film GaAs single junction solar cell with multiple quantum wells inserted in i-region of p-i-n structure. The fabrication process of the thin-film MQW solar cell was developed by transferring epitaxially grown PV active layer to the support substrate by selective wet etching with the InGaP etch-stop layer. Additional grating pattern and high-reflective mirror on the rear surface of thin-film MQW solar cell enhanced the light trapping effect, resulted in over 5 times larger effective optical path length than the physical thickness. Optical characterization of the thin-film MQW solar cell was also attempted to analyze the quasi-Fermi level splitting. Owing to the quantitative electroluminescence (EL) measurement, the internal radiative efficiency can be estimated to the thin-film MQW solar cell. This result indicated that the MQW increased a probability of radiative recombination inside the cell than the bulk GaAs cell.

Free Research Field

半導体工学