Fast-Response Single-Nanowire Photodetector Based on ZnO/WS₂ Core/Shell Heterostructures

Abstract

The surface plays an exceptionally important role in nanoscale materials, exerting a strong influence on their properties. Consequently, even a very thin coating can greatly improve optoelectronic properties of nanostructures by modifying the light absorption and spatial distribution of charge carriers. To use these advantages, 1D/1D heterostructures of ZnO/WS 2 core/shell nanowires with a-few-layers thick WS 2 shell were fabricated. These heterostructures were thoroughly characterized by scanning and transmission electron microscopy, X-ray diffraction and Raman spectroscopy. Then, a single-nanowire photoresistive device was assembled by mechanically positioning ZnO/WS 2 core/shell nanowires onto gold electrodes

Recent Progress of Heterojunction Ultraviolet Photodetectors: Materials, Integrations, and Applications

“…Test conditions: at 1 V bias and under 0.5 W cm −2 illumination of 405, 532, and 660 nm. Reproduced with permission 132. Copyright 2018, American Chemical Society.…”

“…The photoelectric results show that the introduction of a few layers of WS 2 significantly enhances the photoresponse in UV range and drastically shortens the response time by almost two orders of magnitude, compared with the pure ZnO nanowire PD (Figure 3b). 132 A PtSe 2 /GaN heterojunction is fabricated by in situ synthesis of vertically standing 2D PtSe 2 film on n‐GaN substrate. The as‐fabricated heterojunction device demonstrates excellent photoresponse properties in deep‐UV region and presents quick response to 266 nm pulse laser with a rise time of 172 ns 133.…”

2D SnO/In2O3 van der Waals Heterostructure Photodetector Based on Printed Oxide Skin of Liquid Metals

“…The intercepts of the tangents yielding the bandgap energies of the as‐synthesized samples are 4.08 eV for SnO sample and 3.65 eV for In 2 O 3 sample . It is interesting to note that the optical bandgap 2D SnO/In 2 O 3 heterojunction is narrowing to 2.30 eV (Figure S7, Supporting Information) . In order to analyze the synthesized heterojunction further, one commonly used technique in conventional semiconductor to determine the VB offsets is the XPS .…”

ZnO‐Based Ultraviolet Photodetectors with Tunable Spectral Responses

“…However, such devices exhibited only a extremely tiny photocurrent of 11 pA at 5 V under an illumination density of 10 mW cm −2 , which is particularly susceptible to external interference, limiting the practical applications. More recently, ZnO‐based devices with state‐of‐the‐art structures have emerged as one of the most promising candidates for next‐generation UV detection and imaging …”

“…More recently, ZnO-based devices with state-of-the-art structures have emerged as one of the most promising candidates for next-generation UV detection and imaging. [15][16][17] Photoresistors based on ZnO thin films or ZnO nanowires with metal-semiconductor-metal (MSM) structures have been extensively investigated in recent years. [18][19][20] The photoresistors commonly suffer from the slow frequency responses and large dark currents due to the long charge transport length and the lack of blocking layer in the MSM architectures, respectively.…”