秋本  克洋，日本筑波大学  特命教授 

(Prof. K. Akimoto, University of Tsukuba)

秋本 克洋，博士，于1979年在日本京都大学获博士学位，于1979年到1993年在索尼中央研究院从事蓝光激光及发光二极管材料的研发，是蓝光激光器的研究先驱（2003年“日本経済新聞社刊”出版书籍《蓝光LED和激光器的先驱者》，书中位列了日本在发光二极管（LED）和激光器领域杰出的七位科学家，其中有中村修二、赤崎勇、天野浩、秋本克洋等七位教授）。秋本教授于1993到筑波大学从事教学及科研工作，1998年晋升教授，2012至2014年担任筑波大学理学部部长，现任筑波大学特命教授。发表SCI收录文章205篇，著有半导体相关书籍（章节）专著12本，获得美国授权专利8项，日本授权专利26项，任《Journal of Crystal Growth》期刊客座编辑、《Applied Surface Science》期刊顾问编委、《Japan Journal of Applied Physics》编辑委员。

Title: CHARACTERIZATION OF DEFECTS IN Cu(In,Ga)Se₂

Date: Oct. 10, 2019 (Tuesday) 15: 00

Venue: Room 510, MGI

Abstract:

       Considering the limitation of fossil fuels and the environmental issues, development of renewable energy like photovoltaics is highly required. Cu(In_1−x,Gax)Se₂ (CIGS) is one of the most promising material for realizing high efficiency solar cells. The highest conversion efficiency based on CIGS has been reported to be more than 23%, however, it is necessary to improve the crystal quality to get higher performance. In the presentation, recent results on defects in CIGS are presented and guidelines for improving the performance will be discussed. Three kinds of defects were detected and characterized. One has defect level at around 250meV from the valence band and has little effects on the device performance. Another one has defect level at around 800meV from the valence band and works as recombination center. The other one is a formation of impurity phase of Cu₂Se which affects significantly to the device performance. Example of a defect suppression method is discussed.