Extremely Low Dark Current MoS₂ Photodetector via 2D Halide Perovskite as the Electron Reservoir

Abstract

Toward pursuing high‐performance photodetectors based on 2D transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2), it is desirable to reduce the high dark current and sluggish response time. Here, in multilayer MoS2‐based photodetectors, a 2D halide perovskite, (C6H5C2H4NH3)2PbI4 ((PEA)2PbI4), is introduced as a bifunctional material: both as electron reservoir to reduce free carriers and passivation agent to passivate defects. Surprisingly, dark current is suppressed by six orders of magnitude after coating a (PEA)2PbI4 thin layer onto pristine MoS2 photodetector, with the dark current decreased to 10−11 A. This huge reduction of dark current suggests an efficient interlayer charge transfer from MoS2 to (PEA)2PbI4, which is further verified by photoluminescence quenching phenomenon. It indicates that (PEA)2PbI4 serves as electron reservoir to reduce carrier density of MoS2, resulting in ultrahigh detectivity (1.06 × 1013 Jones). Moreover, the response speed is also accelerated by more than 100‐fold due to passivation by 2D perovskite. In addition, it is found that this type of photodetectors can further work at self‐power mode (with the bias of 0 V). Therefore, the strategy of applying 2D perovskite on the surface of TMDs provides a novel way to fabricate high‐performance photodetectors.

MoS2 Based Photodetectors: A Review

“…Recently, Wang et al [ 28 ] have introduced a 2D halide perovskite, (C 6 H 5 C 2 H 4 NH 3 ) 2 PbI 4 ((PEA) 2 PbI 4 ), over a multilayer MoS 2 structure. They achieved a dark current suppression of six orders of magnitude with respect to the neat MoS 2 device, reaching 10 −11 A ( Figure 23 a).…”

“…Thanks to the weak van der Waals interaction between MoS 2 layers, it is possible to obtain mono- or few-layered structures by a simple mechanical exfoliation of bulk MoS 2 [ 22 ]. This approach has been extensively used in many studies [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ] for its intrinsic simplicity, but suffers from some critical issues. In fact, MoS 2 mechanical exfoliation generally leads to very small flakes (lateral size < 10 um) [ 37 ] and it is a low yield process.…”

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

“….2, 27.7, 23.5 to 22.8 ms, and fall times from 69.9, 68.6, 67.4 to 61.5 ms under laser power intensity of 2.5, 16.8, 24.5 and 38.6 mW cm À2 , respectively. PbI 4 ¼ (PEA) 2 PbI 4 with ML MoS 2 has been used to develop hybrid photodetectors by Wang et al367 (PEA) 2 PbI 4 functions as an electron reservoir to decrease free charge carriers as well as a to passivate defects. The dark current was reduced by six orders of magnitude by depositing (PEA) 2 PbI 4 thin lm over MoS 2 photodetector due to the charge transfer from ML MoS 2 to (PEA) 2 PbI 4 thin lm.…”

Engineering sensitivity and spectral range of photodetection in van der Waals materials and hybrids

“…In this manner, the avalanche photodiode is configured as two back-to-back Schottky barriers formed at WS 2 -MoTe 2 heterojunctions which assist in reducing the dark current and their device exhibits detectivity limits of 10 9 Jones. Capping a 2D halide perovskite on MoS 2 has also shown suppression of dark current ∼10 pA leading to detectivity of the order of 10 13 Jones [167]. In this heterostructure, the interlayer charge transfer from MoS 2 to 2D halide leads to six-fold reduction in the dark current value compared to pristine MoS 2 .…”