Characterization of CdMnTe crystal grown with vertical Bridgman method under Te‐rich conditions

Abstract

In this study, the Indium (In) doped Cd1–xMnx Te (xMn=0.1, CdMnTe) crystals with excess Te in the amount of 0 and 1.2 at% were grown by the Bridgman method. The segregation coefficient of In dopants distributions in the CdMnTe crystals with and without excess Te were determined to be 0.08 and 0.11, respectively. The IR transmission microscopy shown that the size of Te inclusions in CdMnTe crystal with excess Te increased to 5–13 μm with the concentrations of (2–3)×105 cm–3. The PL spectra indicated the formation of Te antisite donor and the compensation of Cd vacancies by Te antisites. The Current‐Voltage measurements were performed and the resistivity of the CdMnTe crystal with excess Te was in the range of 108–109 Ω·cm, increased by one order as compared to the crystal without excess Te. Under the radiation of 59.5 keV 241Am, The CdMnTe planar detectors fabricated from the crystal with excess Te revealed the energy resolution of 8.4%, however, no energy response is resolved in the CdMnTe detectors without excess Te. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Structural, electrical, and optical properties of CdMnTe crystals grown by modified floating-zone technique

“…For the CMT crystals grown by Bridgman methods, it was commonly observed that a high density of Te inclusions were formed in the as-grown crystals, especially along grain or twin boundaries. [5,9] These inclusions can distort the local internal electric field in CMT detectors and entail significant fluctuations in the total charge-collection by trapping free charge-carriers, and therefore, seriously deteriorate the performance of radiation detectors. [13] Results of recent quenching experiments clearly showed that the concave growth interface of CMT results in the trapping of Te-rich liquid droplets as a consequence of morphological instability and therefore, a high density of Te inclusions is formed during the subsequent cool-down period.…”

“…[1][2][3] Recently, CMT has attracted increasing interest since it is considered a promising material for the fabrication of high-performance room-temperature x-ray and gammaray detectors. [2][3][4][5] Such detectors offer great potential for nonproliferation applications, medical imaging, astrophysics research, and monitoring industrial processes, because they are able to operate at ambient temperatures, while providing a high detection efficiency and good energy resolution. [6,7] Compared with cadmium zinc telluride (CdZnTe or CZT), a current leading material in such applications, CMT offers several distinct advantages that make it a good candidate in this field.…”

“…Bridgman-grown CMT crystals possess a high density of Te inclusions. [5,9] The micro-scale x-ray response mapping technique and 3D IR transmission microscopy were used to obtain proof that high densities of Te inclusions can entail significant fluctuations in the total collected charge by trapping free charge carriers generated by incident radiation, thereby strongly degrading the energy resolution of thick detectors. [11,12] As a result, it is important to explore new growth techniques to improve the CMT crystal quality.…”

Study of Detector-Grade CdMnTe:In Crystals Obtained by a Multi-Step Post-Growth Annealing Method

“…The phenomenon can be explained by the removal of the impurities [17,22]. Moreover, the DAP peak is relative to the complexes formed by indium and Cd vacancy [24]. Cd atoms diffuse into CMT:In crystals and compensate Cd vacancies in the complexes.…”

Research Progress on Postgrowth Annealing of Cd1−xMnxTe Crystals

“…Thus, the best signal-to-noise ratio of CMT radiation detector can be achieved by relatively low manganese content. [10] Although CMT has many advantages, researchers have encountered many obstacles in studying it. As is known to all, the performance of CMT detector with no defects is better than that of flawed one.…”