Bi_(2)Te_(3)/Si异质结中的侧向光伏效应

Lateral photovoltaic effect in Bi_(2)Te_(3)/Si heterojunction

碲化铋(Bi_(2)Te_(3))是一种典型的拓扑绝缘体材料,在热电、光电和自旋电子学领域具有广阔应用前景.本文采用脉冲激光沉积技术在Si衬底上制备了不同厚度的Bi_(2)Te_(3)薄膜,详细研究了Bi_(2)Te_(3)/Si异质结中的侧向光伏响应特性.结果表明,该异质结的侧向光伏响应强烈依赖于Bi_(2)Te_(3)层厚度,随厚度增加呈现先快速增加至一极值,然后逐渐减小的变化趋势.用不同波长和功率的激光照射测量时发现,该异质结具有405~808 nm的较宽响应波段,且位置灵敏度随激光功率增加而增大并最终趋于饱和,其中671 nm的侧向光伏响应性能最好,最高位置灵敏度达到3.4×10^(-2)V/mm.以上结果为研发基于Bi_(2)Te_(3)的高灵敏、宽波段光位敏探测器提供了重要参考.

Bismuth telluride(Bi_(2)Te_(3))is a typical topological insulator,which has wide application in thermoelectric,optoelectronic and spintronic devices.In this paper,a series of Bi_(2)Te_(3)films were synthesized on the n-type single crystal Si substrate with different thicknesses by pulse laser deposition technology and the lateral photovoltaic effect in them were well studied.The results show that the lateral photovoltage of the heterojunction is strongly dependent on the thickness of Bi_(2)Te_(3)layer.With the increase of the thickness,the lateral photovoltage first increases rapidly to an extreme value,and then decreases gradually.When measured at different wavelengths and laser power,it is found that the heterojunction has a wide response band of 405—808 nm,and the position sensitivity increases with an increase of laser power and finally tends to reach saturation.Among them,the heterojunction shows the best lateral photovoltaic response at 671 nm,and the maximum position sensitivity reaches 3.4×10^(-2)V/mm.This result provides an important experimental basis for the development of Bi_(2)Te_(3)based high sensitivity and broad band light position sensitive detector.