UV-Visible Photodetector Based on I-type Heterostructure of ZnO-QDs/Monolayer MoS2

Abstract

Monolayer MoS2 has shown excellent photoresponse properties, but its promising applications in high-sensitivity photodetection suffer from the atomic-thickness-limited adsorption and band gap-limited spectral selectivity. Here we have carried out investigations on MoS2 monolayer-based photodetectors with and without decoration of ZnO quantum dots (ZnO-QDs) for comparison. Compared with monolayer MoS2 photodetectors, the monolayer ZnO-QDs/MoS2 hybrid device exhibits faster response speed (1.5 s and 1.1 s, respectively), extended broadband photoresponse range (deep UV-visible), and enhanced photoresponse in visible spectrum, such as higher responsivity over 0.084 A/W and larger detectivity of 1.05 × 1011 Jones, which results from considerable injection of carries from ZnO-QDs to MoS2 due to the formation of I-type heterostructure existing in the contact interface of them.

Excited States Calculations of MoS2@ZnO and WS2@ZnO Two-Dimensional Nanocomposites for Water-Splitting Applications

“…Overall, the ε 2 for MoS 2 @ZnO and WS 2 @ZnO is in agreement with those theoretically predicted previously [25][26][27]29]. For most experiments [2,3,72,73], the obvious enhancement of the first peak at absorption spectrum is around 700 nm. Some of the light-trapping structure of core-shell nanopillar array has a great improvement of absorption at the wavelengths below 800 nm [2].…”

“…Zinc oxide (ZnO), one of the potential photocatalysts for water-splitting applications, has been extensively studied at nanoscale for photocatalysis [1], photosensorics [2][3][4][5], and for other industrial applications [6][7][8][9][10][11][12][13], including energy generation by transformation of waste heat energy to electricity through thermoelectric power generation using Al-doped ZnO nanostructures [14,15].…”

“…TMD coatings were produced from WO 3 or MoO 3 thin layers deposited by magnetron sputtering on ZnO nanowires and annealed in a sulfur atmosphere. It has been shown that combining the TMD materials with other wide-gap semiconductors could not only increase their broadband photoresponse but also enhance their absorption in the visible region of solar spectra [3,4,[22][23][24].…”

“…In this study, we have analyzed the photocatalytic properties taking into account the photon excitations. In addition to photocatalysis [2,3], excited states calculations are important for the description of various processes in photostimulated desorption from the solid surfaces [34], photostimulated diffusion and photoinduced transformations of point defects under excitations [35][36][37][38][39], photo-induced exciton relaxation with defect formation [40], and processes of optical storage and optically stimulated luminescence [38,41,42].…”

Two-Dimensional Platinum Diselenide: Synthesis, Emerging Applications, and Future Challenges

“…Moreover, the photoresponsivity in the near-IR (~ 1.47 μm) wavelength range and mid-IR (~ 10 μm) wavelength range is about 5.5 and 4.5 A W −1 , respectively. The fitted rise and fall time for the bilayer PtSe 2 -based photodetector are much better than those 2D materials (such as BP, MoS 2 , and MoSe 2 )-based photodetectors [ 15 , 147 , 149 , 150 , 161 – 166 ]. These results indicate that 2D PtSe 2 is highly promising platforms for high sensitive and broadband optoelectronic application in the range of visible light to mid-IR wavelengths.…”