Point-defect study from low-temperature photoluminescence of CdGa2Se4 layers through the postannealing in various ambient.

The CdGa₂Se₄ layers were grown by the hot-wall epitaxy method. From the absorption measurement, the band-gap variation in CdGa₂Se₄ was well interpreted using Varshni's equation. After the postannealing in various ambient, the behavior of point defects in CdGa₂Se₄ was investigated by measuring photoluminescence (PL). Point defects originating from V_Cd, V_Se, Cd_int, and/or Se_int were classified as donor or acceptor types. Thus, the Ga in CdGa₂Se₄ did not form native defects because the Ga existed in the form of stable bonds in CdGa₂Se₄. Based on these PL results, we schemed out a band diagram of the recombination process in CdGa₂Se₄. [ABSTRACT FROM AUTHOR]