[18p-133-1~10] Current status and future prospect of chalcogenide-based thin film solar cells technology

[18p-133-6] Detection of vacancy-type defects in CIGS filmsby means of positron annihilation

〇Akira Uedono¹, Islam M. M.¹, Sakurai Takeaki¹, Akimoto Katsuhiro¹ (1.Univ. of Tsukuba)

Keywords:CIGS, vacancy, positron

Vacancy-type defects in CIGS grown by a three-stage coevaporation process were probed using monoenergetic positron beams. Measurements of Doppler broadening spectra of the annihilation radiation and positron lifetime spectra showed that two different defect species coexist in the CIGS layers, and these were identified as mono/divacancy-type defects and vacancy clusters, respectively. The vacancy clusters were mainly introduced during the third growth stage, and were located in the subsurface region. The concentration of the defects affected the short-circuit current density and the conversion efficiency of the solar cells. The defect concentration and their depth distributions varied depending on Se beam equivalent pressure, growth time, and post-growth annealing time.