ABSTRACT
We report the photoluminescence (PL) of AgInSe2 crystals grown by the vertical Bridgmann technique. The PL measurements were made at temperatures ranging from 11 K to 315 K and with various excitation powers. At near-band-edge, i.e. the exciton spectral region we found emission peaks at 1.246 eV (B–B), 1.242 eV (E1), and 1.238 eV (E2). Deep PL bands peaking at 1.21 eV (D1), 1.19 eV (D2) and 1.16 eV (D3) are also observed. The intensity of the 1.16 eV PL band quenches rapidly at temperatures T > 40 K with an activation energy of ET = 13 ± 1 meV. For the 1.21 eV band the activation energy is ET= 19 ± 1 meV. It seems reasonable to adopt a donor-acceptor pair (DAP) model for these bands. According to this model the 1.16 eV band is related to a rather deep donor with ED = 72 meV and the 1.21 eV band, in turn, with a shallow donor with ED = 12 meV.
