Abstract
Tin disulfide has substantial importance for two-dimensional material-based optoelectronics and sensors due to its unique optoelectrical properties. In this report, we fabricate SnS2 nanosheets using the low-pressure thermal sulfurization process, whose crystal structure and surface morphology are confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements. From photoconductivity measurement and photocurrent mapping, we observe smaller electrode spacing of SnS2 thin films can enhance photodetection. Then, by the H2O2 oxidation processing, we transform SnS2 to SnO2 to detect humidity. The measured response and recovery time can be optimized to 5.6 and 1.0 s, respectively, shorter than those of commercial DHT11 humidity sensor of 32 and 34 s. At suitable bias, humidity sensor can detect human respiration properly at room temperature. Our results show that SnS2 nanosheets exhibit reasonable performance for emergent photodetector applications and humidity sensing.
Highlights
Transition metal dichalcogenides (TMDC) materials [1,2,3] are attracting intense research interest due to their appreciable band gap in optical and electronical areas
The continuous SnS2 film is composed of flower-like surfaces of nanosheets, which has an advantage for photoresponsivity, similar to SnS2 nanoflake based field effect transistor and high efficiency photodetector [10]
We observe that the SnO2 film remained the similar platelet-shaped nanosheets and from the energy dispersive X-ray spectrum (EDS) analysis we found that the atomic composition ratio of Sn:S is about 34.6:66.4 (Sn):O:S is about 27:70:3
Summary
Transition metal dichalcogenides (TMDC) materials [1,2,3] are attracting intense research interest due to their appreciable band gap in optical and electronical areas. TMDCs including MoS2 [11,12,13], WS2 [14], WSe2 [12,15] and MoTe2 [16] are MX2 stoichiometric compounds, consisting of periodically stacked one transition metal layer and two chalcogenide layers. Among these TMDC semiconductors— SnS2 is less explored compared with MoS2 or WS2—tin (Sn) and sulfur (S) are cheap and abundant on the earth and their potential applications have increased fast. As one important member of metal oxide semiconductors (SnO2, ZnO, WO3), tin dioxide is a typical n-type wide semiconductor with bandgap around 3.7 eV at 300 K [25,26,27], it has been widely used in various applications such as gas sensors [27,28], solar cells [29] and humidity sensors [30]
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