TY - JOUR
T1 - Achieving detector-grade CdTe(Cl) single crystals through vapor-pressure-controlled vertical gradient freeze growth
AU - Yin, Zi Ang
AU - Zhang, Ya Ru
AU - Kang, Zhe
AU - Zhang, Xiang Gang
AU - Liu, Jin Bo
AU - Liu, Ke Jin
AU - Sun, Zheng Yi
AU - Jie, Wan Qi
AU - Zhao, Qing Hua
AU - Wang, Tao
N1 - Publisher Copyright:
© The Author(s), under exclusive licence to China Science Publishing & Media Ltd. (Science Press), Shanghai Institute of Applied Physics, the Chinese Academy of Sciences, Chinese Nuclear Society 2025.
PY - 2025/7
Y1 - 2025/7
N2 - Cadmium telluride (CdTe), which has a high average atomic number and a unique band structure, is a leading material for room-temperature X/γ-ray detectors. Resistivity and mobility are the two most important properties of detector-grade CdTe single crystals. However, despite decades of research, the fabrication of high-resistivity and high-mobility CdTe single crystals faces persistent challenges, primarily because the stoichiometric composition cannot be well controlled owing to the high volatility of Cd under high-temperature conditions. This volatility introduces Te inclusions and cadmium vacancies (VCd) into the as-grown CdTe ingot, which significantly degrades the device performance. In this study, we successfully obtained detector-grade CdTe single crystals by simultaneously employing a Cd reservoir and chlorine (Cl) dopants via a vertical gradient freeze (VGF) method. By installing a Cd reservoir, we can maintain the Cd pressure under the crystal growth conditions, thereby preventing the accumulation of Te in the CdTe ingot. Additionally, the existence of the Cl dopant helps improve the CdTe resistivity by minimizing VCd density through the formation of an acceptor complex (ClTe-VCd)-1. The crystalline quality of the obtained CdTe(Cl) was evidenced by a reduction in large Te inclusions, high optical transmission (60%), and a sharp absorption edge (1.456 eV). The presence of substitutional Cl dopants, known as ClTe+, simultaneously supports the record high resistivity of 1.5×1010Ω·cm and remarkable electron mobility of 1075 ± 88cm2V-1s-1 simultaneously, has been confirmed by photoluminescence spectroscopy. Moreover, using our crystals, we fabricated a planar detector with μτe of (1.11±0.04)×10-4cm2/V, which performed with a decent radiation-detection feature. This study demonstrates that the vapor-pressure-controlled VGF method is a viable technical route for fabricating detector-grade CdTe crystals.
AB - Cadmium telluride (CdTe), which has a high average atomic number and a unique band structure, is a leading material for room-temperature X/γ-ray detectors. Resistivity and mobility are the two most important properties of detector-grade CdTe single crystals. However, despite decades of research, the fabrication of high-resistivity and high-mobility CdTe single crystals faces persistent challenges, primarily because the stoichiometric composition cannot be well controlled owing to the high volatility of Cd under high-temperature conditions. This volatility introduces Te inclusions and cadmium vacancies (VCd) into the as-grown CdTe ingot, which significantly degrades the device performance. In this study, we successfully obtained detector-grade CdTe single crystals by simultaneously employing a Cd reservoir and chlorine (Cl) dopants via a vertical gradient freeze (VGF) method. By installing a Cd reservoir, we can maintain the Cd pressure under the crystal growth conditions, thereby preventing the accumulation of Te in the CdTe ingot. Additionally, the existence of the Cl dopant helps improve the CdTe resistivity by minimizing VCd density through the formation of an acceptor complex (ClTe-VCd)-1. The crystalline quality of the obtained CdTe(Cl) was evidenced by a reduction in large Te inclusions, high optical transmission (60%), and a sharp absorption edge (1.456 eV). The presence of substitutional Cl dopants, known as ClTe+, simultaneously supports the record high resistivity of 1.5×1010Ω·cm and remarkable electron mobility of 1075 ± 88cm2V-1s-1 simultaneously, has been confirmed by photoluminescence spectroscopy. Moreover, using our crystals, we fabricated a planar detector with μτe of (1.11±0.04)×10-4cm2/V, which performed with a decent radiation-detection feature. This study demonstrates that the vapor-pressure-controlled VGF method is a viable technical route for fabricating detector-grade CdTe crystals.
KW - Alpha-detector
KW - CdTe
KW - Semiconductor detector
KW - Vertical gradient freeze method
UR - http://www.scopus.com/inward/record.url?scp=105006688804&partnerID=8YFLogxK
U2 - 10.1007/s41365-025-01707-2
DO - 10.1007/s41365-025-01707-2
M3 - 文章
AN - SCOPUS:105006688804
SN - 1001-8042
VL - 36
JO - Nuclear Science and Techniques
JF - Nuclear Science and Techniques
IS - 7
M1 - 130
ER -