Roy U N, Camarda G S, Cui Y, Gul R, Hossain A, Yang G, Zazvorka J, Dedic V, Franc J, James R B
Brookhaven National Laboratory, Upton, NY, 11973, USA.
North Carolina State University, Raleigh, NC, 27695-7909, USA.
Sci Rep. 2019 Feb 7;9(1):1620. doi: 10.1038/s41598-018-38188-w.
Because of its ideal band gap, high density and high electron mobility-lifetime product, cadmium zinc telluride (CdZnTe or CZT) is currently the best room-temperature compound-semiconductor X- and gamma-ray detector material. However, because of its innate poor thermo-physical properties and above unity segregation coefficient for Zn, the wide spread deployment of this material in large-volume CZT detectors is still limited by the high production cost. The underlying reason for the low yield of high-quality material is that CZT suffers from three major detrimental defects: compositional inhomogeneity, high concentrations of dislocation walls/sub-grain boundary networks and high concentrations of Te inclusions/precipitates. To mitigate all these disadvantages, we report for the first time the effects of the addition of selenium to the CZT matrix. The addition of Se was found to be very effective in arresting the formation of sub-grain boundaries and its networks, significantly reducing Zn segregation, improving compositional homogeneity and resulting in much lower concentrations of Te inclusions/precipitates. Growth of the new quaternary crystal CdZnTeSe (CZTS) by the Traveling Heater Method (THM) is reported in this paper. We have demonstrated the production of much higher yield according to its compositional homogeneity, with substantially lower sub-grain boundaries and their network, and a lower concentration of Te inclusions/precipitates.
由于其理想的带隙、高密度以及高电子迁移率-寿命乘积，碲锌镉（CdZnTe或CZT）目前是最佳的室温化合物半导体X射线和伽马射线探测器材料。然而，由于其固有的热物理性能较差以及锌的分凝系数大于1，这种材料在大体积CZT探测器中的广泛应用仍受到高生产成本的限制。高质量材料产量低的根本原因在于CZT存在三个主要有害缺陷：成分不均匀、高位错壁/亚晶界网络浓度以及高浓度的碲包裹体/沉淀物。为了减轻所有这些缺点，我们首次报道了向CZT基体中添加硒的效果。发现添加硒对于阻止亚晶界及其网络的形成非常有效，能显著减少锌的分凝，改善成分均匀性，并使碲包裹体/沉淀物的浓度大大降低。本文报道了采用移动加热器法（THM）生长新的四元晶体CdZnTeSe（CZTS）。我们已经证明，根据其成分均匀性，产量有了大幅提高，亚晶界及其网络大幅减少，碲包裹体/沉淀物的浓度也降低了。
