Room-Temperature NO₂ Sensing of CVD-Modified WS₂–WSe₂ Heterojunctions

Abstract

semiconducting heterojunction chemical sensors are in high demand because of their enhanced response, stability, and selectivity. However, fine-tuning heterojunctions using vapor deposition growth still needs further research. Our present study focuses on the ambient pressure chemical vapor deposition (CVD) synthesis of hexagonal tungsten sulfide-tungsten selenide (WS 2 −WSe 2 ) p−p heterojunctions (as a 2D−2D arrangement). We use the liquid-phase exfoliation method to disperse bulk WS 2 and WSe 2 and decorate large flakes of WS 2 with smaller WSe 2 nanosheets in CVD. Electron microscopy and related surface investigations reveal their homogeneity on drop-casting. Two drops from the exfoliated heterojunction dispersion were drop-cast on a transducer to study the NO 2 response and related sensing properties. The sensor showed long-term stability (>2 months), even at high humidity levels (40− 90%). The gas-sensing properties of this layered p−p heterojunction-based nanocomposite strongly suggest an affinity toward NO 2 gas, leading to improved response, high stability, independent of humidity effects, and high selectivity.

Transition metal (Ti, Cu, Zn, Pt) single-atom modified graphene/AS2 (A = Mo, W) van der Waals heterostructures for removing airborne pollutants

“…Our previous findings show that pollutant molecule adsorption on the G/MoS 2 and G/WS 2 heterostructures is through physical adsorption. Reports for NO 2 sensing on van der Waals heterostructures like WS 2 –Wse 2 77 have provided good results, yet graphene is very inert. As already known, doping is a way to engineer the reactivity in the graphene sheet, 75 so we now generate single-atom graphene-based heterostructures to evaluate NO 2 , SO 2 , and CO 2 adsorption.…”

Strategic review of gas sensing enhancement ways of 2D tungsten disulfide/selenide-based chemiresistive sensors: decoration and composite

“…The employment of a large-area sensing film and the emergence of a p–p heterostructure between the sensing materials are responsible for the superior sensing mechanism. 200…”

Atomically thin-layered WS2 based resistive sensors for detection of CO and NO2 at room temperature

“…Though the developed sensor shows good sensitivity, the sensor operates at 250 • C [24]. Moumen et al synthesized WS 2 -WSe 2 heterojunction using CVD and could develop an ultrasensitive NO 2 sensor that can operate at room temperature [25]. While the response of the heterojunction to 100 ppb NO 2 is ∼38%, the response times and recovery of the developed sensor were quite long (tens of minutes).…”