title: Improved efficiency of a large-area Cu(In,Ga)Se₂ solar cell by a nontoxic hydrogen-assisted solid Se vapor selenization process.
abstract: A nontoxic hydrogen-assisted solid Se vapor selenization process (HASVS) technique to achieve a large-area (40 × 30 cm(2)) Cu(In,Ga)Se2 (CIGS) solar panel with enhanced efficiencies from 7.1 to 10.8% (12.0% for active area) was demonstrated. The remarkable improvement of efficiency and fill factor comes from improved open circuit voltage (Voc) and reduced dark current due to (1) decreased interface recombination raised from the formation of a widened buried homojunction with n-type Cd(Cu) participation and (2) enhanced separation of electron and hole carriers resulting from the accumulation of Na atoms on the surface of the CIGS film. The effects of microstructural, compositional, and electrical characteristics with hydrogen-assisted Se vapor selenization, including interdiffusion of atoms and formation of buried homojunction, were examined in detail. This methodology can be also applied to CIS (CuInSe2) thin film solar cells with enhanced efficiencies from 5.3% to 8.5% (9.4% for active area) and provides a facile approach to improve quality of CIGS and stimulate the nontoxic progress in the large scale CIGS PV industry.
authors.affiliation: Department of Materials Science and Engineering, National Tsing-Hua University , Hsinchu 30013, Taiwan.
authors.forename: Tsung-Ta
authors.initials: TT
authors.lastname: Wu
authors.forename: Fan
authors.initials: F
authors.lastname: Hu
authors.forename: Jyun-Hong
authors.initials: JH
authors.lastname: Huang
authors.forename: Chia-ho
authors.initials: CH
authors.lastname: Chang
authors.forename: Chih-chung
authors.initials: CC
authors.lastname: Lai
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Yen
authors.forename: Hou-Ying
authors.initials: HY
authors.lastname: Huang
authors.forename: Hwen-Fen
authors.initials: HF
authors.lastname: Hong
authors.forename: Zhiming M
authors.initials: ZM
authors.lastname: Wang
authors.forename: Chang-Hong
authors.initials: CH
authors.lastname: Shen
authors.forename: Jia-Min
authors.initials: JM
authors.lastname: Shieh
authors.forename: Yu-Lun
authors.initials: YL
authors.lastname: Chueh