Facile Fabrication of P(Electrodeposition)/N(Solvothermal) 2D‐WS₂‐Homojunction Based High Performance Photo Responsive, Strain Modulated Piezo‐Phototronic Diode

Abstract

In this work, we demonstrate a low cost, cleanroom free fabrication approach of 2D (2‐dimensional) WS2 p‐n homojunction as a piezo phototronic diode. The p‐type WS2 was deposited over the flexible ITO/PET substrate using electrodeposition technique and the n‐type WS2 was synthesized using very simple and cost‐effective solvothermal technique. XRD and Raman studies confirmed the formation of both p‐type and n‐type WS2 with 3R and 2H structure holding the vibration modes of WS2 .To examine the photoresponsive properties the diode was irradiated with visible light and an increase in 12% of the photo current was observed in the reverse bias with the illumination power intensity of 8.25 mW/cm2 . Further, when the diode was subjected to 0.98% of tensile strain the current was increased up to 91.6%. This enhanced response can be attributed to the piezo‐phototronic effect exhibited by the few layers WS2 structure, which leads to the modulation of the potential at the p‐n junction interface leading to the increase in the carrier concentration of electrons flowing through the device. The p‐n homojunction diode exhibited excellent responsivity and detectivity values of 44.8 A/W and 11.2×1012 Jones respectively with an illumination intensity of 1.26 mW/cm2 and with a very low tensile strain of 0.98% which are higher than those of devices fabricated using sophisticated techniques which find numerous applications in flexible‐electronics.

A Flexible Self‐Powered UV Photodetector and Optical UV Filter Based on β‐Bi2O3/SnO2 Quantum Dots Schottky Heterojunction

“…It can be observed that the transition time between on and off is very less which makes the device faster at 5 V. [ 29 ] Figure 6b shows the rise time calculation at a bias of 0 V and was found to be 0.92 s. The rise time calculation at the bias of 5 V and was found to be 0.1 s shown in Figure S8b, Supporting Information. It is obvious that the rise time with bias is very less because when it is exposed to UV light the generated electron–hole pair is not only experiencing the in‐built electric field but also the external potential that is applied across the device which makes them separate even faster [ 30 ] which increase the current by large amount resulting in rapid response time when compared to the device at the bias of 0 V.…”

Tunable Optical Properties of 2D Materials and Their Applications

“…The p–n homojunction diode showed an excellent responsivity of 44.8 A W −1 and a good detectivity of 11.2 × 10 12 Jones under an illumination intensity of 1.26 mW cm −2 and with a low tensile strain of 0.98%. [ 130 ]…”

“…[51,128,129] For 2D materials applied in piezophototronic diodes, an external strain is induced to form an internal piezoelectric field inside the piezoelectric semiconductors in order to tune the charge separation at the junction interlayer. [130] Xue et al demonstrated an n-type multilayer MoS 2 /p-type GaN film p-n heterojunction photodiode (the inset image of Figure 7a) by piezophototronic effect. The photoresponsivity of this photodiode can be enhanced by 3.5 times attributing to piezophototronic effect from GaN film under a 258 MPa pressure, as illustrated in Figure 7b.…”

Two-Dimensional Metallic NiSe2 Nanoclusters–Based Low-Cost, Flexible, Amperometric Sensor for Detection of Neurological Drug Carbamazepine in Human Sweat Samples

“…Two-dimensional (2D) transition metal dichalcogenides (TMDCs), such as WS 2 , SnSe 2 , FeS 2 , and TaSe 2 , have emerged as potential replacements for organic and silicon-based materials owing to their excellent physical, chemical, and electron transport properties (Ma et al, 2017;Veeralingam et al, 2019aVeeralingam et al, ,b,c, 2020Veeralingam and Badhulika, 2020a). NiSe 2 , a layered metallic TMDC, possesses unique physical, optical, and electrochemical properties viz., high carrier mobility, and large surface-to-volume ratio that makes it well-suited for applications such as batteries and supercapacitors (Wang et al, 2017).…”

“…In particular, the zero bandgap and intrinsic electrical conductivity (Swesi et al, 2017) of NiSe 2 structure make it a potential candidate for excellent electron transfer-assisted sensing applications. NiSe 2 has been synthesized using various methods such as direct stoichiometric process (Anantharaj et al, 2019), precipitation (Mani et al, 2017), thermal decomposition, and hydrothermal (Veeralingam et al, 2019a), and solvothermal reactions (Yu et al, 2017). However, precipitation technique requires intermittent processing steps due to slow diffusion and insolubility of Se atoms.…”