The effect of Te solution volume on the growth of CdZnTe crystals by Traveling Heater Method

Nowadays, Traveling Heater Method (THM) is demonstrated to be one of the most promising ways to grow high-quality CdZnTe (CZT) crystals. The THM is essentially a melt-solution growth method, in which the CZT solute diffuses from the dissolution interface to the growth interface in the Te solution and deposits on the CZT seed. In this work, the effects of Te solution volumes on the structure of CZT solute, growth interface, defects and electrical properties of CZT crystals grown by THM were investigated. CZT crystals (φ30 × 80 mm3) were grown by THM with different volumes of Te solution (H/D = 1.5, 1, and 0.5, where H is the height and D is the diameter of Te solution). The distribution and morphology of CZT solutes in different Te solutions were investigated, which shown that the large-sized CZT solute in Te solution is more conducive to single-crystal growth and the growth temperature is calculated to be 806–809 °C. The growth interfaces correlated with Te inclusions in the as-grown CZT crystals were revealed, which shown that the CZT crystal grown with Te solution of H/D = 1 has a planar growth interface and the lowest Te concentration. The size of Te inclusion is mainly in the range of 3–10 μm in all CZT crystals grown by THM. The IR transmittance of different CZT wafers was conducted in the range of 4000–500 cm−1. The resistivity and energy spectra of CZT detectors under 241Am irradiation were measured at room temperature. The experiment results demonstrated that the Te solution volume with H/D = 1.0 is optimal for the stable growth of high-quality CZT crystals by THM.