Volodymyr D. Popovych

Dyson line and modified Dyson line in the EPR measurements

Abstract The difficulty in determining the electron paramagnetic resonance (EPR) line parameters of ferromagnetic semiconductors has been addressed. For these materials, the resonance line is very broad and lies at low resonance field, so that only a part of the line can be detected experimentally. Moreover, the line is of asymmetric (Dysonian) shape as described by the line shape parameter α. We have compared values of line parameters derived by computer fitting of the whole experimental EPR line to the Dyson function (or modified Dyson function) with the values obtained by applying this procedure to the left and the right half of the line.

Nature of nonlinearity of I-V characteristics in CdTe:Cl single crystals

The current-voltage characteristics are investigated in single crystals of CdTe doped with Cl. Measured samples were ntype conductivity with resistivity ρ=(0.5-2.0)×108 Ohm×cm, electron concentration n=(0.5÷2.0)×108 cm-3 and electron mobility μ=280÷300 cm2/Vxs. Experimental data are explained in the framework of theory of highly doped and highly compensated (HDHC) semiconductors. The mobility-lifetime product measured at room temperature is found to be of the order of (1÷5)x 10-4 cm2xV-1. It means that this material can be used for manufacture of X-ray detectors.

Characterization of CdCrTe Layers Obtained by Pulsed Laser Deposition

In this paper we have obtained CdCrTe thin layers by PLD method using the YAG:Nd3+ laser with pulse length 250μs. Synthesized CdCrTe solid solution with 50% at. of Cr has been taken as a target. The layers were deposited on KCl substrate. The target and films were analyzed using X-ray diffraction, TEM microscope and THEED electron diffraction. The morphology of the layers are homogenous. However, we have detected several crystallographic phases: cubic CdTe, hexagonal Cr and hexagonal Te. From the measurements of lattice constant of the layer, their composition was determined to be x=0,14

Noise Properties Of High Resistivity Cl‐doped Cadmium Telluride

Investigation of noise properties of CdTe:Cl samples with specific resistivity in the range ρ ≈ 108 – 109 Ωcm at room temperature were performed. Cadmium telluride single crystals with chlorine concentration in the range NCl = 1017 – 5 × 1019 cm−3) were grown by sublimation traveling heater method (STHM). Noise spectra have been measured over a wide range of frequencies, from below 1 Hz up to 1 MHz, and for voltages applied the samples from 0 up to 200 V. Two type of noise dominates in the range of voltages and frequencies under investigation, namely excess 1/f noise and generation‐recombination (G‐R) noise. Analyses of short noise were performed taking into consideration the presence of the macrodefects and clusters (inclusions and precipitates) in the crystalline matrix. It is assumed that these types of inhomogeneities affect the current noise spectra especially in highly doped material (NCl > 1019 cm−3).

Electrical properties of CdTe:Cl single crystals grown by sublimation technique

The current-voltage characteristics are investigated in single crystals of CdTe doped with Cl. Measured samples were n -type conductivity with resistivity ρ=(0.5-2.0)x108 Ohmxcm, electron concentration n =(0.5 ÷ 2.0)x108 cm-3 and electron mobility μ = 280 ÷ 300 cm2/Vxs. Experimental data are explained in the framework of theory of highly doped and highly compensated semiconductors. The mobility-lifetime product measured at room temperature is found to be in the order of (1÷5)x10-4 cm2xV-1. It means that this material can be used for manufacture of X-ray detectors.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.