Advantages of a Special Post-Growth THM Program for the Reduction of Inclusions in CdTe Crystals

Abstract

CdTe crystals are used widely for manufacturing gamma-ray radiation sensors, and we can improve their properties if we eliminate as many as possible of their Te inclusions. In this paper, we describe our two modes of removing them; first, we used the traveling heater method for growing them, and then we applied post-growth cooling, for which we used a special slow-cooling program. Here, we placed the CdTe ingot, containing inclusions, into a quartz container, and moved a narrow heater zone along it. The molten inclusions moved together with the hot zone, and, at end of the process, they were concentrated heavily at the ingot's surface. Consequently, very few inclusions were observed in much of the CdTe ingot. Hall effect measurements showed that after such annealing the value of the carrier mobility was increased significantly, and the concentration of ionized centers was reduced. One major advantage of this treatment, compared to thermal annealing alone, is that both the inclusions and impurities are eliminated simultaneously.

Effect of Compensation Degree on the Detecting Properties of In-doped Cd0.9Zn0.1Te crystals

“…Recently, the most popular method of doped CdTe and Cd 1-х Zn х Te crystals' growth for the manufacturing of detectors and spectrometers is the method of vertical zone melting through tellurium solution-melt -the method of travelling heater (THM) [4,[9][10][11][12][13][14]. The advantage of this method is the growth of crystals at a much lower temperature (1020 K) and additional purification of the material with the tellurium zone.…”

Mechanisms contributing to dark current across metal/CdMnTe/metal structures

“…CdTe was proposed as a promising material for X/γ-ray detectors in early 1960s [2]. Further developments put CdTe ahead of other semiconductor candidate materials [3][4][5][6][7]. The main advantage of CdTe detectors in comparison to high-purity germanium is the ability to operate without cryogenic cooling and the greater sensitivity to higher X-or gamma-ray energies due to the higher atomic numbers of Cd and Te.…”

Purification of the Cd(Mn)Te For X-ray Detector Crystals by Special Annealing

“…This modification was called the method of «dry zone» (MDZ). The application of the MDZ to CdTe crystals [7] led to considerably reduction of Te inclusions and also to the transformation in point defects system. In particular, the common concentration of ionized centers decreased that led to conductivity type change.…”