Ultrasensitive MoS2 photodetector by serial nano-bridge multi-heterojunction

Abstract

The recent reports of various photodetectors based on molybdenum disulfide (MoS2) field effect transistors showed that it was difficult to obtain optoelectronic performances in the broad detection range [visible–infrared (IR)] applicable to various fields. Here, by forming a mono-/multi-layer nano-bridge multi-heterojunction structure (more than > 300 junctions with 25 nm intervals) through the selective layer control of multi-layer MoS2, a photodetector with ultrasensitive optoelectronic performances in a broad spectral range (photoresponsivity of 2.67 × 106 A/W at λ = 520 nm and 1.65 × 104 A/W at λ = 1064 nm) superior to the previously reported MoS2-based photodetectors could be successfully fabricated. The nano-bridge multi-heterojunction is believed to be an important device technology that can be applied to broadband light sensing, highly sensitive fluorescence imaging, ultrasensitive biomedical diagnostics, and ultrafast optoelectronic integrated circuits through the formation of a nanoscale serial multi-heterojunction, just by adding a selective layer control process.

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

“…The role of conguration of device heterojunctions has been emphasized for developing high performance MoS 2 photodetectors. Kim et al 348 reported MoS 2 photodetectors using serial nano-bridge multi-heterojunctions. The MoS 2 photodetectors based on laser irradiation were assigned as type (1) monolayer, type (2) multilayer, type (3) parallel heterojunction, type (4) serial heterojunction, type (5) parallel nanobridge multi-heterojunction, and type (6) serial nano-bridge multi-heterojunction.…”

Detectivity optimization to measure ultraweak light fluxes using an EM-CCD as binary photon counter array

“…In the past 30 years, considerable efforts have been successfully devoted to best detect single photons emitted by discrete sub-wavelength size objects such as single molecules, or to localize such point-like emitters when sparsely distributed over an object field. This has led to a huge diversity of methods aimed at single photon detection and imaging [1][2][3][4][5] .…”

The New Etching Technologies of Graphene Surfaces

“…Bandgap tuning for nanomaterials will significantly improve the on/off current ratio, photoresponsivity, quantum efficiency, conductivity and others. Layer-by-layer etching for multilayer materials by low-energy plasma technology (double mesh grids inserted for plasma apparatus such as chlorineradical ICP, neutral-beam ICP and ion beam ICP) with no physical damage would be the next research direction and can be applied to the other low-dimensional materials [28,43] to achieve ultrahigh performance of electronic and optoelectronic devices [28,43]. For instance, in the latest report in 2019, Kim et al utilized a chlorine ICP innovative plasma apparatus that has no physical damage effect by inserting double mesh grids for cyclic ALE process on intrinsic multilayer MoS 2 and successfully fabricated heterostructured photodetector with ultra-responsivity (~10 6 A/W) in the visible range [43].…”