Carrier transport and trapping process in photorefractive CdTe:V

Time-resolved photoelectric spectroscopy measurements of photorefractive CdTe:V crystals were carried out by using a short light pulse with 9 ns duration from a nitrogen laser (337.1 nm). The light pulse was focused through the semitransparency Au-electrode. The stationary monochromatic illumination of crystals allowed to measure the time-resolved photocurrent, which is caused by the detrapping of electrons photogenerated by the pulse laser excitation. The dependence of intensity of pulse photocurrent at the delay time t(d) = 5 ns, which corresponds to its maximum value, on the energy of additional monochromatic illumination was investigated. In this case the spectral dependence of pulse photocurrent caused by the detrapping process of electrons in CdTe:V crystals has been measured under the different intensity of the electric field. It was shown that the additional illumination at h(omega) < E-g leads to the increasing of photocurrent intensity that is caused by the detrapping processes of electrons from impurity centers and intrinsic defects. Obtained results indicate that CdTe:V crystals are high-sensitive ultrafast photorefractive materials which may be also used for the elaboration of fast photodetectors in the near IR-region.