Improving the photoelectrical characteristics of self-powered p-GaN film/n-ZnO nanowires heterojunction ultraviolet photodetectors through gallium and indium co-doping
Improving the photoelectrical characteristics of self-powered p-GaN film/n-ZnO nanowires heterojunction ultraviolet photodetectors through gallium and indium co-doping
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DOI：
10.1016/j.mssp.2020.105295
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发表时间：
2021-01-01
影响因子：
4.1
通讯作者：
Hsu, Cheng-Liang
中科院分区：
文献类型：
--
作者：
Tsay, Chien-Yie;Hsiao, I-Ping;Hsu, Cheng-Liang
采用低温水热法在蓝宝石/p-GaN薄膜模板上生长ZnO、Ga掺杂ZnO（GZO）、In掺杂ZnO（IZO）和Ga-In共掺杂ZnO（GIZO）纳米线阵列，用于制备自供电的p-GaN/n-ZnO异质结紫外（UV）光电探测器。研究了Ga、In单掺杂和Ga-In共掺杂对水热合成ZnO纳米线的微结构特征和光学性能的影响，并对4种p-n异质结紫外探测器的光电响应特性进行了比较研究。X射线衍射（XRD）分析表明，所制备的ZnO基纳米线阵列为单相六方纤锌矿结构，并呈现出沿着（002）面的择优取向。扫描电子显微镜（SEM）观察表明，掺杂剂的类型改变了纳米线的形态和平均直径。ZnO基纳米线的平均直径为61-101 nm。室温光致发光（PL）光谱表明，这些合成的ZnO基纳米线具有较高的结晶质量。基于p-GaN薄膜/n-ZnO基纳米线阵列的异质结光电探测器的I-V曲线在黑暗和紫外光照射下呈现整流特性。在紫外光照射下，GIZO器件在5 V偏压下具有最好的光敏特性。在5 V偏压下，光暗电流比接近6.0，开启电压低于1.8 V。与单掺杂和未掺杂ZnO器件相比，所提出的p-GaN/n-GIZO异质结紫外光电探测器在零偏压下实现了上级的光响应性能。
ZnO, Ga-doped ZnO (GZO), In-doped ZnO (IZO), and Ga-In co-doped ZnO (GIZO) nanowire arrays were grown on a template of sapphire/p-GaN thin film by low-temperature hydrothermal method for fabricating self -powered p-GaN/n-ZnO heterojunction ultraviolet (UV) photodetectors. The authors investigated the effects of Ga or In single doping and Ga-In co-doping on the microstructural features and optical properties of hydro -thermally synthesized ZnO nanowires and conducted a comparison study on the photosensing characteristics and photoelectrical response performances of four kinds of p-n heterojunction UV photodetectors. X-ray diffraction (XRD) examination showed that the as-synthesized ZnO-based nanowire arrays had a single-phase hexagonal wurtzite structure and exhibited a preferential orientation along the (002) plane. Scanning electron microscope (SEM) observation evidenced that the type of dopants modified the morphology and average diameter of the nanowires. The average diameter of ZnO-based nanowires was in the range of 61-101 nm. Room-temperature photoluminescence (PL) spectra revealed that these as-synthesized ZnO-based nanowires had high crystalline quality. The current-voltage (I-V) curves of heterojunction photodetectors based on p-GaN thin film/n-ZnO based nanowire arrays exhibited a rectification characteristic in darkness and under UV illumination. Under UV illumination, the GIZO device had the best photosensing characteristics of all the devices under 5 V bias. The light-to-dark current ratio was close to 6.0 at 5 V bias and the turn-on voltage was lower than 1.8 V. The presented p-GaN/n-GIZO heterojunction UV photodetector realized superior photoresponse performance at zero -bias voltage as compared to single-doped and un-doped ZnO devices.