High quality of CdSe single crystal is grown from the melt. X-ray
fluorescence (XRF) showed that the ingot crystal has Cd:Se ratio very close to 1.
The Photoresponse spectra in the energy range 1.2- 2.1 eV is found to change with
increasing temperature from 80 K to 300 K. At temperatures ≤ 200 K three peaks
are observed at 1.45; 1.73 and 1.97 eV; whereas above 200 K, the peaks at 1.45
and 1.97 eV are washed out. These peaks are interpreted in terms of the band
model, considering the band splitting. The photocurrent-temperature behaviour
showed three main regimes: a weak dependence at lower temperatures; thermal
quenching region (maximum at 200 K) and a marked decrease at higher
temperatures. The onsets and offsets of the three regions are found to depend on
the incident photon energy. A very high lifetime (milliseconds); being temperature
dependent is obtained from the frequency resolved photoconductivity. The data are
explained on the bases of recombination kinetics controlled by defect centres.