Multilayer WSe₂/MoS₂ Heterojunction Phototransistors through Periodically Arrayed Nanopore Structures for Bandgap Engineering

Abstract

While 2D transition metal dichalcogenides (TMDs) are promising building blocks for various optoelectronic applications, limitations remain for multilayered TMD‐based photodetectors: an indirect bandgap and a short carrier lifetime by strongly bound excitons. Accordingly, multilayered TMDs with a direct bandgap and an enhanced carrier lifetime are required for the development of various optoelectronic devices. Here, periodically arrayed nanopore structures (PANS) are proposed for improving the efficiency of multilayered p‐WSe2/n‐MoS2 phototransistors. Density functional theory calculations as well as photoluminescence and time‐resolved photoluminescence measurements are performed to characterize the photodetector figures of merit of multilayered p‐WSe2/n‐MoS2 heterostructures with PANS. The characteristics of the heterojunction devices with PANS reveal an enhanced responsivity and detectivity measured under 405 nm laser excitation, which at 1.7 × 104 A W−1 and 1.7 × 1013 Jones are almost two orders of magnitude higher than those of pristine devices, 3.6 × 102 A W−1 and 3.6 × 1011 Jones, respectively. Such enhanced optical properties of WSe2/MoS2 heterojunctions with PANS represent a significant step toward next‐generation optoelectronic applications.

Zero Dimensional–Two Dimensional Hybrid Photodetectors Using Multilayer MoS2 and Lead Halide Perovskite Quantum Dots with a Tunable Bandgap

“…However, a near-unity exponent of 0 < α < 1 is shown in hybrid photodetectors based on 2D materials as a result of the complex processes of carrier generation, trapping, and recombination within a 2D semiconductor. 33 In Figure 4d, the power law relationships of the lead halide PQDs/MoS 2 hybrid photodetectors estimated from experimental data show I photo ∝ P 0.4∼0.5 . To calculate the responsivity of 0D−2D hybrid photodetectors, using the measured photocurrent increments and illumination powers, the following equation was used: = R…”

“…For an ideal photodetector device, the photocurrent is expected to show a linear dependence (α = 1). However, a near-unity exponent of 0 < α < 1 is shown in hybrid photodetectors based on 2D materials as a result of the complex processes of carrier generation, trapping, and recombination within a 2D semiconductor . In Figure d, the power law relationships of the lead halide PQDs/MoS 2 hybrid photodetectors estimated from experimental data show I photo ∝ P 0.4∼0.5 .…”

Boosting the Sensitivity of WSe2 Phototransistor via Janus Interfaces with 2D Perovskite and Ferroelectric Layers

“…As shown in Figure g, the device still displays an obvious photoresponse even under ultraweak light intensity as low as 1.6 nW/cm 2 , while R is 2.3 × 10 5 A/W and D * is 4.1 × 10 14 Jones under the test condition of V g = 0, V ds = 0.1 V (the spectral noise density measured under dark conditions with V ds = 0.1 V is shown in Figure S10). Figure h summarizes the competitive values of threshold light intensity in the field of 2D semiconductor-based photodetectors, ,,,,,,,, in which our device is the best. The excellent performance in weak-light detection ability for our device mainly stems from the vertical Janus-interface device architecture, combining with the upper perovskite for providing generous photoexcited holes to WSe 2 and the lower ferroelectric film for suppressing the dark current dramatically.…”

Nanostructured doping of WSe2via block copolymer patterns and its self-powered photodetector application

“…10 An infrared WSe 2 -based photodetector with high sensitivity was reported with a vertical heterojunction structure between WSe 2 and black phosphorus. 11 To collect more electron–hole pairs (EHPs) efficiently generated by photon absorption, different device architectures have been proposed, including forming p–n homo- 12 or heterojunctions 13 and integrating with quantum dots, 59 polymers, 14 or perovskites. 15…”