Water- and Humidity-Enhanced UV Detector by Using p-Type La-Doped ZnO Nanowires on Flexible Polyimide Substrate
Water- and Humidity-Enhanced UV Detector by Using p-Type La-Doped ZnO Nanowires on Flexible Polyimide Substrate
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DOI：
10.1021/am403364r
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发表时间：
2013-11-13
影响因子：
9.5
通讯作者：
Hsueh, Ting-Jen
中科院分区：
文献类型：
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作者：
Hsu, Cheng-Liang;Li, Hsieh-Heng;Hsueh, Ting-Jen
采用水热法在柔性聚酰亚胺衬底上生长了高密度La掺杂ZnO纳米线。纳米线的长度和直径分别约为860 nm和80-160 nm。La掺杂样品的XRD峰均向较大的角度移动。La掺杂样品的强PL峰位于380 nm，接近ZnO的3.3 eV带隙。光致发光占主导地位，说明掺La样品中存在大量的氧空位。当通过HR-TEM测量时，类似于0.514 nm的ZnO：La NW的晶格常数较小。EDX光谱确定掺杂La的样品含有约1.27原子%的La。通过霍尔效应测量发现La掺杂的样品为p型。p-ZnO：La纳米线的暗电流随着相对湿度（RH）的增加而减小，而p-ZnO：La纳米线的光电流随着RH的增加而增加。较高的相对湿度环境改善了紫外响应性能。基于最高98%RH，光电流/暗电流比为约47.73。与40%RH相比，p-ZnO：La纳米线上的水滴的UV响应约为2个数量级。在水环境中，p-ZnO：La纳米线的光电流/暗电流比为212.1，这是最大的紫外响应。
High-density La-doped ZnO nanowires (NWs) were grown hydrothermally on flexible polyimide substrate. The length and diameter of the NWs were around 860 nm and 80-160 nm, respectively. All XRD peaks of the La-doped sample shift to a larger angle. The strong PL peak of the La-doped sample is 380 nm, which is close to the 3.3 eV ZnO bandgap. That PL dominated indicates that the La-doped sample has a great amount of oxygen vacancies. The lattice constants,similar to 0.514 nm of the ZnO:La NW were smaller when measured by HR-TEM. The EDX spectrum determined that the La-doped sample contains approximately 1.27 at % La. The La-doped sample was found to be p-type by Hall Effect measurement. The dark current of the p-ZnO:La NWs decreased with increased relative humidity (RH), while the photocurrent of the p-ZnO:La nanowires increased with increased RH. The higher RH environment was improved that UV response performance. Based on the highest 98% RH, the photocurrent/dark current ratio was around 47.73. The UV response of water drops on the p-ZnO:La NWs was around 2 orders compared to 40% RH. In a water environment, the photocurrent/dark current ratio of p-ZnO:La NWs was 212.1, which is the maximum UV response.