TY - JOUR
T1 - Compensation processes in high-resistivity CdZnTe crystals doped with In/Al
AU - Nan, Ruihua
AU - Wang, Tao
AU - Xu, Gang
AU - Zhu, Man
AU - Jie, Wanqi
N1 - Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - The high resistivity performances for aluminum/indium doped Cd0.9Zn0.1Te crystals (CZT:Al/CZT:In), grown via the modified vertical Bridgman method and under excess Cd/Te conditions, were investigated by the relationship between Al/In dopant behaviors and defects induced by crystal growth. Subsequently, their defects compensation processes responsible for high resistivity were proposed by thermally stimulated current spectroscopy. It was revealed that the donor levels from impurity Al/In are too shallow to account for the Fermi level pinned near the mid-gap of CZT materials. Considering the growth of CZT:Al crystal under Cd-rich condition, the doubly ionized Cd interstitial (Cdi2+) as a deep donor was formed with an activation energy of 0.554 eV. Correspondingly, a deep donor level of doubly ionized Te antisite (TeCd2+) located at 0.704 eV was observed in CZT:In crystal grown under Te-rich condition. In addition, the Fermi level dominated by deep level defects were evaluated at 0.716 eV for CZT:Al and 0.740 eV for CZT:In by the temperature-dependent resistivity using current-voltage measurements, which almost approach the mid-gap. We therefore suggest that these deep donor defects (TeCd2+/Cdi2+) can stabilize the Fermi level deep near the mid-gap and thus result in high resistivity.
AB - The high resistivity performances for aluminum/indium doped Cd0.9Zn0.1Te crystals (CZT:Al/CZT:In), grown via the modified vertical Bridgman method and under excess Cd/Te conditions, were investigated by the relationship between Al/In dopant behaviors and defects induced by crystal growth. Subsequently, their defects compensation processes responsible for high resistivity were proposed by thermally stimulated current spectroscopy. It was revealed that the donor levels from impurity Al/In are too shallow to account for the Fermi level pinned near the mid-gap of CZT materials. Considering the growth of CZT:Al crystal under Cd-rich condition, the doubly ionized Cd interstitial (Cdi2+) as a deep donor was formed with an activation energy of 0.554 eV. Correspondingly, a deep donor level of doubly ionized Te antisite (TeCd2+) located at 0.704 eV was observed in CZT:In crystal grown under Te-rich condition. In addition, the Fermi level dominated by deep level defects were evaluated at 0.716 eV for CZT:Al and 0.740 eV for CZT:In by the temperature-dependent resistivity using current-voltage measurements, which almost approach the mid-gap. We therefore suggest that these deep donor defects (TeCd2+/Cdi2+) can stabilize the Fermi level deep near the mid-gap and thus result in high resistivity.
KW - A1. Defects
KW - A2. Bridgman technique
KW - B1. Cadmium compounds
KW - B2. Semiconducting II–VI materials
UR - http://www.scopus.com/inward/record.url?scp=84994480565&partnerID=8YFLogxK
U2 - 10.1016/j.jcrysgro.2016.07.032
DO - 10.1016/j.jcrysgro.2016.07.032
M3 - 文章
AN - SCOPUS:84994480565
SN - 0022-0248
VL - 451
SP - 150
EP - 154
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
ER -