Improved Carrier Transport and Enhanced Detection Sensitivity Through Zr4+ Doping in LiYMo2O8 Single Crystals for
Qian Yang1, Lulu Dong2, Feifei Guo1
1State Key Laboratory of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan 250100, China.
Abstract:
X-ray detectors play an important role in medical imaging, security inspection, industrial nondestructive testing, and high-energy physics. Oxide single crystals are attractive candidates for direct X-ray detection because of their high chemical stability, good mechanical robustness, and feasibility for large-size crystal growth. However, their ultrahigh intrinsic resistivity often limits photocurrent generation and thus restricts detection sensitivity. Here, Zr doping is proposed as a strategy to regulate carrier transport in LiYMo2O8 (LYMO) single crystals. Pristine LYMO and Zr-doped LYMO crystals were successfully grown by the top-seeded solution growth method. The pristine LYMO crystal exhibits resistivities of 9.96 × 1013 and 1.44 × 1014 Ω cm along the a- and c-axes, respectively, with corresponding mobility-lifetime (μτ) products of 1.15 × 10-3 and 1.81 × 10-3 cm2 V-1. After Zr incorporation, the a-axis resistivity decreases to 5.68 × 109 Ω cm, while the μτ product increases to 8.97 × 10-3 cm2 V-1. As a result, the a-axis X-ray sensitivity reaches 431 μC Gy-1 cm-2 under 40 keV X-ray irradiation, more than twice that of the pristine LYMO detector. The Zr-doped LYMO detector also maintains low detection limits of 50.1 and 29.8 nGy s-1 along the a- and c-axes, respectively. These results demonstrate that rational Zr4+ donor doping is an effective approach to balancing resistivity, charge collection efficiency, and baseline stability in high-resistivity oxide crystals for improved X-ray detection.
