Resistivities, carrier concentrations, optical absorption, and photoluminescences of undoped and Cd,Zn-doped CuAlSe2 single crystals grown by chemical vapor transport were studied. The electrical and optical properties were almost unchanged after annealing under Se pressure. However, the resistivity increased about seven orders of magnitude after annealing in vacuum. The resistivity also increased by Cd or Zn doping. The samples showed p-type conduction even when Cd or Zn was doped. An acceptor ionization energy of about 65 meV was obtained. The mobility showed the dominance of lattice scattering for temperatures between 80 and 200 K. Two independent, broad, red luminescences having their own excitation energies were observed at relatively low temperature. We have proposed the configuration coordinate model for this characteristic emission. The emission can be interpreted as radiative transitions from a deep center to the respective A or C valence bands, accompanied by a lattice relaxation.
ASJC Scopus subject areas
- Physics and Astronomy(all)