Ko Yeong Hwan, Nagaraju Goli, Yu Jae Su
Department of Electronics and Radio Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, South Korea.
Nanoscale. 2015 Feb 14;7(6):2735-42. doi: 10.1039/c4nr06662f.
We report the facile fabrication of wire-shaped ultraviolet photodetectors (WUPDs) by employing a nanostructured zinc oxide (ZnO)/nickel oxide (NiO) coaxial p-n heterojunction. The WUPD consists of a ZnO/NiO coaxial Ni wire and a twisted gold (Au) wire where the Ni and Au are used as the anode and cathode, respectively. For the coaxial p-n heterojunction, the NiO nanostructures (NSs) and the ZnO nanorods (NRs) are subsequently formed on the surface of Ni wire via thermal oxidation and hydrothermal growth processes. With an applied bias of -3.5 V, the WUPD exhibits good photoresponsivity of 7.37 A W(-1) and an external quantum efficiency of 28.1% at an incident light wavelength of 325 nm. Under the UV illumination at a wavelength of 365 nm, the dark current and photocurrent are -3.97 × 10(-7) and -8.47 × 10(-6) A, respectively. For enhancing the photocurrent, the WUPD is threaded through a silver (Ag) coated glass tube which acts as a waveguide to concentrate the UV light of 365 nm on the WUPD. As a result, the photocurrent is significantly improved up to -1.56 × 10(-5) A (i.e., 1.84 times) at the reverse bias of -3.5 V.
我们报道了通过采用纳米结构的氧化锌（ZnO）/氧化镍（NiO）同轴p-n异质结来简便制备线状紫外光电探测器（WUPD）。该WUPD由一根ZnO/NiO同轴镍丝和一根扭曲的金线（Au）组成，其中Ni和Au分别用作阳极和阴极。对于同轴p-n异质结，通过热氧化和水热生长过程，在镍丝表面依次形成NiO纳米结构（NSs）和ZnO纳米棒（NRs）。在施加-3.5 V偏压时，该WUPD在325 nm入射光波长下表现出7.37 A W⁻¹的良好光响应度和28.1%的外量子效率。在365 nm波长的紫外光照下，暗电流和光电流分别为-3.97×10⁻⁷ A和-8.47×10⁻⁶ A。为了增强光电流，将WUPD穿过一根涂有银（Ag）的玻璃管，该玻璃管用作波导，将365 nm的紫外光集中在WUPD上。结果，在-3.5 V的反向偏压下，光电流显著提高至-1.56×10⁻⁵ A（即1.84倍）。
