PHOTOLUMINESCENCE AND PHOTOLUMINESCENCE EXCITATION STUDY OF CUGATE2

Photoluminescence (PL) and photoluminescence excitation measurements o ver a temperature range 12 K < T < 300 K on high quality CuGaTe2 cryst als grown by the vertical Bridgman method were completed. The whole PL spectrum consists of two regions. The first region includes PL bands El at 1.431 eV, E-2 at 1.426 eV, and E-3 at 1.417 eV, together with th eir phonon replicas while in the second region we have a PL band D-0 a t 1.338 eV with its well-resolved LO-phonon replicas ((h) over bar ome ga(LO) = 26.5 meV). All these PL bands appear to be at higher energy t han the lowest (fundamental) band gap energy E-g(A). The possible orig in of observed PL bands is discussed. (C) 1998 American Institute of P hysics.