Vertically Stacked MoSe₂/MoO₂ Nanolayered Photodetectors with Tunable Photoresponses

Abstract

A variety of two-dimensional (2D) nanodevices with diverse optoelectronic properties have been successfully fabricated. A strategy for engineering 2D heterostructures high-performance devices rich in functions and adaptable for specific applications must be developed. Herein, two types of photodetectors fabricated through van der Waals interactions from vertically stacked MoSe 2 / MoO 2 heterostructures with the thickness of MoO 2 flakes at 25 and 105 nm, respectively, which exhibits metallic and semiconductor characteristics on elevation at thickness from 25 to 105 nm. A higher photoresponse can be obtained from the thin MoO 2 flake vertically stacked MoSe 2 /MoO 2 heterostructure with the merits of a photoresponsivity of 100.86 mA•W −1 and a detectivity of 23.4 × 10 9 Jones. The external quantum efficiency reaches 23.5% at bias of 3 V under the illumination of a monochromatic light at 532 nm, which is better than thick MoO 2 flake heterostructure (thickness ∼ 105 nm). The enhanced mechanism originates from high absorption efficiency, high carrier conductivity, and better contact of thin metallic MoO 2 flakes compared to the thick MoO 2 flakes heterostructure, which relates to various Fermi energy levels of the two different MoO 2 flakes photodetector. This work can provide an interesting route for engineering optoelectronic high-performance devices and developing a diverse photodetector on the basis of transition metal dichalcogenides (TMDs)/transition metal oxides (TMOs) heterojunction.

MoSe2 Nanosheets with Tuneable Optical Properties for Broadband Visible Light Photodetection

“…EQE spectra of the device shown in Figure d are found to be broad at different bias conditions, and a maximum EQE peak of 50% is observed at a wavelength of 460 nm under 1 V bias, revealing the efficient generation of photo-induced charge careers. Wazir et al have reported CVD grown MoSe 2 /MoO 3 heterojunction photodetector and obtained an EQE ∼23.5% with the excitation of 532 nm laser at a bias of 3 V. In contrast, in this work, we have obtained a much superior photoresponse and EQE (up to ∼50%) at an applied bias of 1 V in the entire visible region using solution-processed MSM-type device, demonstrating the efficacy of our devices.…”

Single-Layer MoS2 Grown on Atomically Flat SrTiO3 Single Crystal for Enhanced Trionic Luminescence

“…In the extensively explored FSH systems, the two-dimensional materials (2DM) have emerged as an important participator owing to their remarkable properties including the superior conductivity, high chemical stability, conspicuously large surface area, as well as luminescing properties, etc . − The combination of 2DM with transition metal oxides (TMO) frequently constitutes more fascinating heterostructures seeing broad applications in various fields such as solar cells, photoconductors, photodetectors, and so on. − In such systems, a serious control of the interface structure can be more critical because the properties of the oxides can be sensitively dependent on their atomic structures and the ad-species, the latter may impose unexpected affections on the overall functionality of the heterostructure. As a representative of these FSH, the compositional system of MoS 2 and SrTiO 3 has attracted much interest considering the attractive properties of both materials. − Particularly, SrTiO 3 differs from many other oxides in its distinctive layered structure, high dielectric constant, quantum paraelectricity, etc . , and thus being expected with a special tuning effect over the MoS 2 properties.…”

2D Ultrawide Bandgap Semiconductors: Odyssey and Challenges

“…performance of ultraviolet photodetectors is not enough for the requirement. Until now, various methods have been exploited to improve the property of ultraviolet photodetectors, like van der Waals heterojunction integration, [201][202][203][204][205][206][207][208][209][210] ferroelectric modulation, [211] surface functionalization, [212] and doping. [213][214][215]…”