Optical and photoelectric properties of vanadium-doped Cd1$minus$xHgxTe crystals

Abstract

Vanadium-doped semi-insulating Cd1−xHgxTe (x < 0.05) n-type crystals were grown by the Bridgman technique for the first time. Studies were carried out of the low-temperature optical and photoelectric properties of Cd1−xHgxTe (x = 0.014), which provided information on the deep anisotropic impurity centres and intrinsic defects. The nature and the position of their energy levels with respect to the crystal energy band were determined. It was shown that for the investigated crystals there are two photogeneration mechanisms of electrons from deep impurity levels: the auto-ionization of electrons from the discrete state, which is in resonance with the conduction band, and their direct photoionization. It was found that the photosensitivity region for Cd0.986Hg0.014Te:V crystals is about 1.3 μ m.

Study of the structural and photoluminescence properties of CdTe polycrystalline films deposited by close-spaced vacuum sublimation

“…At the same time, the line at 1.545 eV may be caused by the recombination of the donor electrons with the energy E c -0.010 eV and the acceptor holes with E v + 0.050 eV. In this case the acceptor level corresponds to the single charged cadmium vacancies [30][31][32][33].…”

Time-resolved photoelectric spectroscopy of photorefractive CdTe:V crystals

“…The absorption and photodiffusion current (PDC) spectra were measured with a KSVU-23 device at T = 78 K. The PDC measurement technique was presented in detail in [9]. The time dependence of the shape of the laser pulse and the spectral distribution of pulse photocurrent (PPC) were measured using the stroboscopic system of registration with the time window equal to about 0.1 ns.…”

“…The absorption spectra of CdTe crystal doped with vanadium atoms and those of pure CdTe were investigated at 78 K in [9]. The spectrum of CdTe:V reveals absorption bands in the transparency region of pure CdTe.…”

“…The presence of V 3+ ions in CdTe:V crystals was also detected in [8] by measuring the impurity photoluminescence spectra of CdTe:V at T = 4.2 K. The wide absorption band near 1.20 eV is due to both the intracentre transitions between the 4 T 1 (F) states of V 2+ impurity ions in CdTe and its overlap with the photoionizing absorption. It was established [9] that the excited 4 T 1 (P) state of V 2+ impurity ions in CdTe crystals is in resonance with the conduction band.…”

Spectroscopic study of V doped Hg0.018Cd0.981Mn0.001Te bulk crystals as near-infrared materials for optical applications

“…[10][11][12] In the case of Cd 1−X Hg X Te both the band gap of the crystals and the photoionization energy of the dopants decreased as compared to CdTe. This makes it possible to extend the photosensitivity range of these crystals to longer wavelengths.…”