DEEP CENTER LUMINESCENCE IN P-TYPE CDTE

The deep-level photoluminescence (PL) emission in the 1.1 eV spectral region in p-type CdTe:Cl polycrystalline samples was studied as a unct ion of the excitation laser power and temperature. The relatively broa d 1.1 eV PL band has a nonsymmetrical shape which can be easily change d by varying the excitation laser power. Detailed analysis of the line shape shows that the 1.1 eV emission contains two distinct separate b ands. These two bands have their zero-phonon peaks located at 1.08 and 1.17 eV, respectively, and they have quite different half-widths. A d onor-acceptor (DA) pair model with a deep donor and a deep acceptor wi th E(D) and E(A) both >0.5 eV is proposed to explain the observed expe rimental findings. In this model the 1.08 and 1.17 eV bands are formed as a DA recombination between pairs of the nearest neighbors, and bet ween pairs of the next-nearest neighbors, respectively. It is conclude d that the acceptor in these pairs must be an interstitial atom. One p ossible realization for this kind of a DA pair is the V-Te-Te-i comple x, where V-Te is acting as a donor and Te-i as an acceptor. (C) 1996 A merican Institute of Physics.