High-responsivity UV-Vis Photodetector Based on Transferable WS2 Film Deposited by Magnetron Sputtering

Abstract

The two-dimensional layered semiconducting tungsten disulfide (WS2) film exhibits great promising prospects in the photoelectrical applications because of its unique photoelectrical conversion property. Herein, in this paper, we report the simple and scalable fabrication of homogeneous, large-size and transferable WS2 films with tens-of-nanometers thickness through magnetron sputtering and post annealing process. The produced WS2 films with low resistance (4.2 kΩ) are used to fabricate broadband sensitive photodetectors in the ultraviolet to visible region. The photodetectors exhibit excellent photoresponse properties, with a high responsivity of 53.3 A/W and a high detectivity of 1.22 × 1011 Jones at 365 nm. The strategy reported paves new way towards the large scale growth of transferable high quality, uniform WS2 films for various important applications including high performance photodetectors, solar cell, photoelectrochemical cell and so on.

Low-cost VO2(M1) thin films synthesized by ultrasonic nebulized spray pyrolysis of an aqueous combustion mixture for IR photodetection

“…where R l is responsivity, A is the effective area of the detector in cm 2 , q is the electron charge, I d is the dark current, P l is the power density and I ph is the photocurrent. [75][76][77] Our device showed high detectivity of D* ¼ 2.43 Â 10 10 and 3.53 Â 10 10 jones at bias voltage of 5 and 10 V respectively at 200 mW cm À2 power density under 1064 nm laser. We also calculated the photoconductive gain (G) dened as the ratio of the number of electrons collected per unit time (N el ) to the number of absorbed photons per unit time (N ph ) from the relation 78 G ¼ N el /N ph ¼ R l [1.24/l(mm)h] ¼ s/s tr ¼ I ph /qF where R l is responsivity of the detector, l is the incident light wavelength, h is quantum efficiency, s is hole (minority) lifetime, s tr is electron transit time, I ph is photocurrent, q is the elementary charge, and F is the photon absorption rate and found it to be equal to G ¼ 9.99 Â 10 3 .…”

“…Responsivity indicates how the efficiency of the detector responds to the optical signal. 74 It is dened as the photocurrent generated per unit power of incident light on the effective area 75 and is given by R l ¼ I ph /P l A where I ph is the photocurrent, P l is the power density and A is the effective area of the device. 45,76 High responsivity indicates that a large photocurrent can be achieved under a relatively low optical input.…”

Fast photoresponse and high detectivity in copper indium selenide (CuIn 7 Se 11 ) phototransistors

“…The opto-electronic measurements for device I is shown in figure 2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 µ is the carrier mobility) across the channel resulting in more drain current [26].…”

Technique and model for modifying the saturable absorption (SA) properties of 2D nanofilms by considering interband exciton recombination

“…In the past few years, the emergence of 2D transition metal dichalcogenides (TMDs), e.g., MX 2 (M = Mo, W; X = S, Se), has attracted increasing attention because of their wide bandgap range from near-infrared to the visible region 19 and their unique and favorable electrical, optical, thermal and mechanical properties. 20 Layered TMDs are a new class of functional materials and have been used extensively in various applications such as nanoelectronics, 21 solar cells, 22 photodetectors, 23 nonlinear optics [24][25][26] photocatalysis 27 and energy storage. 28 Molybdenum disulfide (MoS 2 ) is the most studied member of the TMD family for nonlinear optical applications, [29][30][31] and very recently, the novel tungsten disulfide (WS 2 ) began to receive significant attention because of its tunable bandgap arising from indirect-to-direct bandgap transition with a decreasing number of layers, high carrier mobility and strong spin-orbit coupling due to its asymmetric structure and favorable photonic properties.…”