Deep level emission in polycrystalline CuGaSe2 thin-films observed by micro-photoluminescence

作者：Islam, Muhammad Monirul^*; Wang, Shenghao; Ishizuka, Shogo; Shibata, Hajime; Niki, Shigeru; Akimoto, Katsuhiro; Sakurai, Takeaki

来源：Japanese Journal of Applied Physics, 2018, 57(8): 08RC02.

DOI：10.7567/JJAP.57.08RC02

• SINGLE-CRYSTALS
• ELECTRICAL-PROPERTIES
• ELECTRONIC-STRUCTURE
• EPITAXIAL LAYERS
• SOLAR-CELLS
• CUINSE2
• BAND
• ENERGY
• CHALCOPYRITES
• DEPENDENCE

Polycrystalline CuGaSe2 thin-films with various Cu-contents were deposited by three-stage co-evaporation method. Radiative transitions in the CuGaSe2 were studied by micro-photoluminescence technique in relation to the Cu/Ga ratio in the films. In addition to a peak DAP1 around 1.60 eV, a peak DAP2 at relatively lower energy of 1.35 eV and a broadened deep-level emission DL roughly centered at 1.05 eV were observed in the photoluminescence (PL) spectra of the CuGaSe2 films. Excitation-power dependence along with temperature dependence of the PL suggests that dominant recombination mechanism due to donor-acceptor pair recombination at lower temperature becomes impurity-to-band transition at higher temperature for all the three peaks. A deep donor-level, roughly 630 meV below the conduction band, which corresponds to DL-emission has been confirmed, and was investigated further in relation to the compositional variation in the CuGaSe2 films.

• 出版日期2018-8
• 单位上海大学