Self‐Powered Broad Spectral Photodetector with Ultrahigh Responsivity and Fast Response Based on Sb₂Se₃/VO₂ Heterojunction

Abstract

despite the advantages of being without outer energy, most self-powered photodetectors suffer from low photoresponsivity, hindering their commercial applications. Even with recent progresses, for those devices with relatively high responsivity, the slow response time remains another challenge. [14] Therefore, constructing a self-powered broadband photodetector with high responsivity and fast response time is of great importance.Antimony triselenide (Sb 2 Se 3 ), with advantages of suitable bandgap, [15] high absorption coefficient, excellent electronic properties, low toxicity, low cost, and relatively earth-abundant constituents, [16] has attracted great research attention for solar cells and photodetectors. [17][18][19] Vanadium oxides, especially VO 2 , are typical materials with strong electron correlations and metal-insulator transitions, which are promising for smart windows, optic switches, memories, etc. [20][21][22][23][24][25][26][27] In this study, we fabricated a bilayer film of Sb 2 Se 3 and VO 2 on a sapphire substrate, forming a heterojunction photodetector. Despite its simple structure, the photodetector shows a superhigh responsivity of 0.244 A W −1 without any outer bias and fast response speeds of 200 µs for rise and 360 µs for decay. It should be emphasized that our self-powered photodetectors possess both high responsivity and fast response speed simultaneously. Great prospect for commercial applications can be imagined on this bilayer device.

High-Performance Photodetectors with an Ultrahigh Photoswitching Ratio and a Very Fast Response Speed in Self-Powered Cu2ZnSnS4/CdS PN Heterojunctions

“…The I−V curve (red) is consistent with the diode output characteristics, which also proves the existence of a PN junction of the CZTS and CdS layers. Moreover, a rectification factor, defined as R F = |I forward /I reverse |, reaches above 39 at |V ds | = 2 V; to our knowledge, this R F value is comparable to some solar cells and photodiodes, such as the Schottky junction solar cells of graphene/GaAs (R F = 24, |V ds | = 1 V), 24 van der Waals heterostructures of WSe 2 /MoS 2 (R F = 50, |V ds | = 8 V), and so on, 25,26 as indicated by the I−V curve (blue) on a logarithmic scale. The inset of Figure 2a shows the I−V characteristics in the dark and in the presence of light irradiation.…”

“…This, therefore, yields an ultrahigh photoswitching ratio of ≈2 × 10 4 . Such a high switching ratio is 10−20 times larger than those of the self-powered photodetectors, such as the n-Si/p-GaTe heterojunction (I light /I dark ratio of 10 3 ) 38 and the Sb 2 Se 3 /VO 2 heterojunction (I light /I dark ratio of 1211) 26 and even comparable to those of the photodetectors with an ultrahigh on/off ratio including the Se/ZnO PN junction (I light /I dark ratio of 10 4 ) 39 and the GaN/ Sn:Ga 2 O 3 PN junction (I light /I dark ratio of 10 4 ). 40 Furthermore, the periodical and constant on/off switching behaviors after a continuous operation above 200 s indicate cyclic stability of the CZTS/CdS photodetectors.…”

Molecular Imprinted Poly(2,5-benzimidazole)-Modified VO2–CuWO4 Homotype Heterojunction for Photoelectrochemical Dopamine Sensing

“…Such a higher PI PEC suggests that the introduction of n−n type-II VO 2 / CuWO 4 could improve charge transport efficiency due to the generation of robust built-in electric field, which could restrain defect recombination. 58 The open-circuit voltage (OCV) switching response of asprepared photoelectrodes under light irradiation (Figure 3c) showed a sharp increase in the anodic photopotential of MIP/ VO 2 /CuWO 4 /Ti due to the generation of electron−hole pair and built-in electric field. The photovoltage variation of MIP/ VO 2 /CuWO 4 /Ti was much higher than in other samples which can be correlated to the superior charge separation, transport, and transfer efficiency.…”

Enhanced Photoelectric Properties of Multilayer Graphene Mg2Si/Si Heterojunction Photodetector

“…Moreover, the peak value of the on/off ratio is increased from 142 to 629 by increasing the number of Graphene layers. The on/off ratio of Gr/Si PD was reported as 100 in [40], and 10 for BLG/Si PD in [41]. The on/off ratio of 3LGr/Si PD was reported as 100 in [2] as shown in Table 2.…”