Zhou Weichang, Zhou Yong, Peng Yuehua, Zhang Yong, Yin Yanling, Tang Dongsheng
Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, College of Physics and Information Science, Hunan Normal University, Changsha 410081, People's Republic of China.
Nanotechnology. 2014 Nov 7;25(44):445202. doi: 10.1088/0957-4484/25/44/445202. Epub 2014 Oct 14.
Optoelectronic diode based on PN heterostructure is one of the most fundamental device building blocks with extensive applications. Here we reported the fabrication and optoelectronic properties of GaTe/Sn : CdS nanoflake/nanowire PN heterojunction photodetectors. With high quality contacts between metal electrodes and Sn : CdS or GaTe, the electrical measurement of GaTe/Sn : CdS hybrid heterojunction under dark condition demonstrates an excellent diode characteristic with well-defined current rectification behavior. The photocurrent increases drastically under LED white light as well as red, green, UV illumination. The on-off ratio of current is about 100 for forward bias and 3000 for reverse bias, which clearly indicates the ultrahigh sensitivity of the heterostructure photodetector to white light. The responsivity and optical gain are determined to be 607 A W(-1) and (1.06-2.16) × 10(5)%, which is higher than previous reports of single GaTe or CdS nanostructures. Combination the Ids-Vds curves under different illumination power with energy band diagrams, we assign that both the light modulation effect under forward and reverse bias and the surface molecular oxygen adsorption/desorption mechanism are dominant to the electrical transport behavior of GaTe/Sn : CdS heterojunction. This heterostructure photodetector also shows good stability and fast response speed. Both the high photosensibility and fast response time described in the present study suggest strongly that the GaTe/Sn : CdS hybrid heterostructure is a promising candidate for photodetection, optical sensing and switching devices.
基于PN异质结构的光电二极管是应用广泛的最基本的器件构建模块之一。在此，我们报道了GaTe/Sn:CdS纳米片/纳米线PN异质结光电探测器的制备及其光电特性。由于金属电极与Sn:CdS或GaTe之间具有高质量的接触，GaTe/Sn:CdS混合异质结在黑暗条件下的电学测量显示出优异的二极管特性，具有明确的电流整流行为。在LED白光以及红、绿、紫外光照射下，光电流急剧增加。正向偏置时电流的开/关比约为100，反向偏置时约为3000，这清楚地表明了该异质结构光电探测器对白光的超高灵敏度。响应度和光学增益分别确定为607 A W(-1)和(1.06 - 2.16)×10(5)%，高于先前关于单一GaTe或CdS纳米结构的报道。结合不同光照功率下的Ids-Vds曲线和能带图，我们认为正向和反向偏置下的光调制效应以及表面分子氧吸附/解吸机制对GaTe/Sn:CdS异质结的电输运行为起主导作用。这种异质结构光电探测器还表现出良好的稳定性和快速响应速度。本研究中描述的高光敏性和快速响应时间都有力地表明，GaTe/Sn:CdS混合异质结构是光探测、光学传感和开关器件的有前途的候选材料。
