High‐Performance Photodiode Based on Atomically Thin WSe₂/MoS₂ Nanoscroll Integration

Abstract

Self‐assembled structures of 2D materials with novel physical and chemical properties, such as the good electrical and optoelectrical performance in nanoscrolls, have attracted a lot of attention. However, high photoresponse speed as well as high responsivity cannot be achieved simultaneously in the nanoscrolls. Here, a photodiode consisting of single MoS2 nanoscrolls and a p‐type WSe2 is demonstrated and shows excellent photovoltaic characteristics with a large open‐circuit voltage of 0.18 V and high current intensity. Benefiting from the heterostructure, the dark current is suppressed resulting in an increased ratio of photocurrent to dark current (two orders of magnitude higher than the single MoS2 nanoscroll device). Furthermore, it yields high responsivity of 0.3 A W−1 (corresponding high external quantum efficiency of ≈75%) and fast response time of 5 ms, simultaneously. The response speed is increased by three orders of magnitude over the single MoS2 nanoscroll device. In addition, broadband photoresponse up to near‐infrared could be achieved. This atomically thin WSe2/MoS2 nanoscroll integration not only overcomes the disadvantage of MoS2 nanoscrolls, but also demonstrates a single nanoscroll‐based heterostructure with high performance, promising its potential in the future optoelectronic applications.

Self‐Driven WSe2/Bi2O2Se Van der Waals Heterostructure Photodetectors with High Light On/Off Ratio and Fast Response

“…On the other hand, we calculated the important indicators of photovoltaic energy conversion: fill factor (FF) and external quantum efficiency (EQE) for our WSe 2 /Bi 2 O 2 Se self‐driven detector by the formula: FF = P el,max /( I sc V oc ) and EQE = ( I ph / P )( hc / qλ ) = R ( hc / qλ ) (where h is the Planck constant, q is the unit charge and λ is the excitation wavelength). [ 41,60 ] From the Figure 5e, the WSe 2 /Bi 2 O 2 Se heterostructure obtained maximum FF of 0.24 and EQE up to 66.27% under 52.27 and 1.12 mW cm −2 , respectively, which is comparable to reported values based on MoS 2 /WSe 2 (1.5%, 34%), [ 47,59 ] MoS 2 /BP (0.3%) [ 41 ] and AsP/InSe (1.5%). [ 42 ] The power conversion efficiency defined as η PV = P el / P in was calculated ≈ 0.428% under 52.27 mW cm −2 .…”

Mechanically rollable photodetectors enabled by centimetre-scale 2D MoS2 layer/TOCN composites

“…[52][53][54] Based on the above equation, the average R values were calculated to be 63.57 and 131.02 µA/W for the 1 and 4 nm samples, respectively. The results also show that the photo-responsivity does not degrade with increasing illumination intensity, unlike the previous observations with 2D MoS2 layers prepared on other planar substrates, [55][56][57][58][59] indicating that these 2D MoS2 layers/TOCN composites maintain excellent structural integrity (See Fig. S4, ESI †).…”

A review of molybdenum disulfide (MoS2) based photodetectors: from ultra-broadband, self-powered to flexible devices

“…This study showed low-power consumption MoS 2 nanoscroll-based photodetections where avalanche multiplication effect enhanced the photoresponsivity in MoS 2 nanoscrolls compared with atomically thin monolayer MoS 2 . Deng et al 381 reported photodiodes having p-type WSe 2 and single MoS 2 nanoscrolls which showed suppressed dark current and two orders of magnitude increase in the ratio of photocurrent to dark current compared with a single MoS 2 nanoscroll-based photodiode. Fig.…”