Group II-VI narrow band gap compounds CdTe, ZnCdTe and CdSeTe are known as the most suitable semiconductor materials for the room temperature γ- and X-ray detectors. In this work, electronic properties of a quadrupole compound ZnCdSeTe were investigated. Chlorine, copper and oxygen doped host material was synthesized from the grinded mixture of 2 mol% ZnTe, 36 mol% CdTe, and 62 mol% CdSe, to keep a hexagonal structure of crystals. Precautions were applied to achieve an uniform doping, high quality of the crystal surfaces, and to remove residue phases after the thermal treatments. Fabricated polycrystalline samples showed a high performance from NIR via VIS and UV to X-ray band, with sharp donor-acceptor pair peak at 922 nm, and dynamic range above 104. High stability, good linearity and performance of samples was measured using X-ray source with Cu-anode, at 40 kV.
A new high efficiency, low-bandgap phosphor, ZnSe:Cu,Ce,Cl is described which exhibits a significantly higher quantum gain than conventional x-ray phosphors and more closely matches the spectral sensitivity of silicon sensors. For many imaging applications this phosphor thus promises significantly superior performance compared to conventional phosphors.
Results on the influence of annealing in vacuum and in Te vapors to the dark and light resistance's (RD and RL) of CdTe:Cl miniature crystals (300 - 400 micrometer) of monograin powders is reported and discussed. The dark to light resistance ratio 105 (RD equals 1011 (Omega) ) at incandescent light intensity of 104 1x at room temperature have been obtained for 400 micrometer size CdTe:Cl round-shape monograins. Process of annealing was found to shrink the porous structure of as-grown CdTe monograins and to smooth the crystal surfaces.
The possibility is demonstrated to manufacture by the recrystallization of initial powders in different molten fluxes different A2B6 powders with the qualities acceptable for monograin layer construction. Several technologies of formation of monograin layers and optoelectronic devices were developed and studied. It is shown, that insufficient electronic parameters of semiconductor sensors and solar cells designed as monograin layers are connected with the insufficient cleaning of surfaces of crystals in the monograin layer.
This paper discusses the recrystallization mechanism, kinetics and morphology of the crystals of different A2B6 powders versus preparation conditions. It is shown that these parameters are mainly determined by the chemical nature and concentration of a flux.