Few-Layer PdSe₂ Nanofilm/Si Heterojunction for Sensing NO₂ at Room Temperature

Abstract

Palladium diselenide (PdSe 2 ), a noble transition metal dichalcogenide has attracted increasing attention in recent years due to its outstanding semiconductor properties. In this study, 2D PdSe 2 nanofilms with thicknesses ranging from 2 to 28 nm and their heterostructures with Si substrates (PdSe 2 /Si heterostructures) were synthesized via a simple selenization method. Electrical transport characterizations based on field-effect transistor devices indicate that the few-layer PdSe 2 nanofilms exhibit a p-type semiconducting behavior. The optimal sensing performance of the PdSe 2 /Si-8 sensor (8 nm-thick PdSe 2 ) exhibits a comparable response toward NO 2 gas (ΔR/R a = ∼7.2% to 100 ppb and ∼18% to 1 ppm) at room temperature (RT). This response may result from the heterostructure effect and maze-type surface. Additionally, the PdSe 2 /Si-8 sensor has selectivity toward NO 2 compared with other gases including NO, H 2 , CO, NH 3 , and C 2 H 5 OH. Furthermore, density functional theory (DFT) calculations reveal the largest adsorption energy and charge transfer between NO 2 and the PdSe 2 surface, which coincides well with the experimental results. Moreover, the PdSe 2 /Si-8 sensor also exhibits repeatability and long-term stability during about 4 months at RT. These results indicate that the PdSe 2 /Si heterostructures may be a promising nanomaterial for room-temperature NO 2 gassensing devices.

UV-light-assisted gas sensor based on PdSe2/InSe heterojunction for ppb-level NO2 sensing at room temperature

“…1(c), the major peaks at 337.1, 342.3, 55.0, and 55.9 eV observed in the PdSe 2 spectrum are assigned to Pd 3d 5/2 , Pd 3d 3/2 , Se 3d 5/2 , and Se 3d 3/2 , respectively. 11 Besides, the peak positions with the binding energies of 444.6, 452.2, 54.2, and 55.0 eV in the InSe XPS can be attributed to In 3d 5/2 , In 3d 3/2 , Se 3d 5/2 , and Se 3d 3/2 , respectively. 24 The full spectra and the elemental compositions of the PdSe 2 and InSe films after fitting with the mixed Gaussian–Lorentzian function are shown in Fig.…”

“…10 Recently, PdSe 2 and InSe have been reported as the promising room-temperature gas sensing materials due to their unique crystal structures and properties. 11,12 Furthermore, the vdWs heterostructures formed by two different TMDs materials can compete with or even be superior to conventional bulk semiconductor junctions and respective 2D constituent because of their atomically sharp interfaces and designed energy band alignments. 13 Recent studies have shown that the vdWs heterostructures devices with outstanding performance have been widely investigated in the fields of photodetectors, field-effect transistors (FETs), solar cells, and room-temperature gas sensors.…”

Pentagonal 2D Transition Metal Dichalcogenides: PdSe2 and Beyond

“…Strategies for preparing other low-dimensional Reproduced with permission. [220] Copyright 2021, American Chemical Society. c) SEM image of a pentagonal PdSe 2 nanosheet (cathode) protruding from metal lead 1 and the anode W-tip used for field emission measurements.…”

“…Afterwards, the gas sensor of PdSe 2 /Si heterostructure is experimentally demonstrated and they analyzed the charge transfers between the PdSe 2 surface and molecules of C 2 H 5 OH, CO, H 2 , NH 3 , NO, and NO 2 , respectively ( Figure a). [ 220 ] The gas sensor presents excellent selectivity and the highest response of 42% toward 5 ppm NO 2 among the six studied gases at room temperature (Figure 14b), due to the specific surface morphology and p‐n heterostructure effect. Meanwhile, the gas sensor with an excellent response of about 7.2% toward 100 ppb NO 2 gas shows extremely low limit of detection, indicating the promising applications of pentagonal 2D materials for consumer electronics, industrial safety, medical and health, environmental protection, and aerospace after their response and recovery times can be further improved.…”

“…a) Charge transfers between the surface of pentagonal PdSe 2 and the molecules of C 2 H 5 OH, CO, H 2 , NH 3 , NO, and NO 2 . b) Response comparison of the pentagonal PdSe 2 /Si-8 sensor for various gases at room temperature.Reproduced with permission [220]. Copyright 2021, American Chemical Society.…”