Highly Sensitive Photodetectors Based on WS_(2)Quantum Dots/GaAs Heterostructures

The performance of the photodetector is significantly impacted by the inherent surface faults in GaAs nanowires(NWs).We combined three-dimensional(3D)gallium arsenide nanowires with zero-dimensional(0D)WS_(2)quantum dot(QDs)materials in a simple and convenient way to form a heterogeneous structure.Various performance enhancements have been realized through the formation of typeⅡenergy bands in heterostructures,opening up new research directions for the future development of photodetector devices.This work successfully fabricated a high-sensitivity photodetector based on WS_(2)QDs/GaAs NWs heterostructure.Under 660 nm laser excitation,the photodetector exhibits a responsivity of 368.07 A/W,a detectivity of 2.7×10^(12)Jones,an external quantum efficiency of 6.47×10^(2)%,a low-noise equivalent power of 2.27×10^(-17)W·Hz-1/2,a response time of 0.3 s,and a recovery time of 2.12 s.This study provides a new solution for the preparation of high-performance GaAs detectors and promotes the development of optoelectronic devices for GaAs NWs.

CdSe量子点敏化对GaAs发光特性的影响

为了探究量子点敏化对GaAs衬底发光性能的影响,采用化学沉积法制备了CdSe量子点,将量子点沉积在GaAs衬底上进行敏化。采用X射线衍射测试确认物相,利用扫描电子显微镜对量子点的形貌进行表征,并通过荧光光谱测试对CdSe量子点敏化后的GaAs衬底样品与未敏化的样品进行对比。结果表明:所制备的CdSe量子点大小均匀,尺寸约为20 nm,且均匀地附着在GaAs衬底上,CdSe量子点/GaAs形成了Ⅱ型能带结构。量子点敏化使GaAs衬底表面的载流子浓度升高。通过荧光光谱测试对各发光峰的来源进行了分析。测试数据显示,与敏化前相比,敏化后的GaAs衬底带边发光增强了2.25倍,缺陷发光增强了3倍。