PtSe₂ Field-Effect Phototransistor with Positive and Negative Photoconductivity

Abstract

Platinum diselenide (PtSe 2 ) has been exploited for visible and infrared photodetectors due to its tunable electrical and photoelectric properties determined by a layer-dependent band gap. We investigated the photoconductive mechanism of the fewlayer (3 nm) PtSe 2 field-effect phototransistor (FEPT) under illumination of visible and infrared lasers. The few-layer PtSe 2 FEPT shows ambipolar characteristics modulated by a gate voltage with a mobility of 1496.7 cm 2 v −1 s −1 (electron) and 1410 cm 2 v −1 s −1 (hole) at V DS = 0.16 V. Both positive photoconductivity (PPC) and negative photoconductivity (NPC) were observed in the PtSe 2 photodetector. The responsivity (R) of the device at V G = 4 V was 0.14 A/W, 0.63 A/W, and 0.086 A/W, and the specific detectivity (D*) was 4.34 × 10 8 Jones, 1.95 × 10 9 Jones, and 2.4 × 10 8 Jones under 532, 808, and 405 nm laser irradiation, respectively. The R of the device at V G = −2.4 V was 0.525 A/W, 0.34 A/W, and 0.087 A/W, and theD* was 1.84 × 10 9 Jones 1.06 × 10 9 Jones, and 2.19 × 10 8 Jones. The change of the photoconductivity is attributed to a combination of three mechanisms: (1) photoinduced desorption of oxygen molecules from the surface, which is related to the NPC; (2) the photoinduced carriers, which leads to PPC; and (3) the photogating effects related to the photoinduced electrons in the interface of PtSe 2 /SiO 2 . NPC dominates in the device at a high gate voltage due to the photogating effect. Through the study of the P/NPC mechanism in PtSe 2 , understanding of the photoconductive mechanism in the field of photoelectric detection is further deepened.

Research Process on Photodetectors based on Group‐10 Transition Metal Dichalcogenides

“…Various techniques such as the formation of Schottky barrier height, contact engineering, and Schottky Mott rule have been reported to reduce the contact resistance and boost the devices' performance. vdWs gaps in the surface of TMDCs are the main reason for the increased [179] Copyright 2022, American Chemical Society. d) Schematic diagram of PtS 2 -based phototransistor.…”

“…Reproduced with permission. [ 179 ] Copyright 2022, American Chemical Society. d) Schematic diagram of PtS 2 ‐based phototransistor.…”

“…c) Schematic diagram of PtSe 2 -based phototransistor with negative and positive conductivity. Reproduced with permission [179]. Copyright 2022, American Chemical Society.…”

Optically Controlling Broadband Terahertz Modulator Based on Layer-Dependent PtSe2 Nanofilms

“…One needs to find the material with high carrier mobility, short carrier relaxation time, and significant surface conductivity for the modulator [26,27]. As novel transition metal dichalcogenide (TMDCs) materials, PtSe 2 and its parental compounds such as PtTe 2 , PdTe 2 , and NiTe 2 have been widely studied by researchers for their unique energy band structure and novel physical properties [28][29][30][31]. However, PtSe 2 stands out due to its unique properties of having high carrier mobility, an adjustable band gap of 0-1.2 eV, and fast response characteristics [32][33][34].…”

Interfacial electronic properties between PtSe2and 2D metal electrodes: a first-principles simulation

“…[26][27][28][29][30][31][32] It has applications in optoelectronics, gas sensors, and catalysis and possesses thermoelectric properties which are at the forefront of research in physics, chemistry, engineering, and materials science. [33][34][35][36][37][38][39][40][41] High-performance PtSe 2 FETs with ON/OFF ratios of up to 10 8 and good gate modulation properties at room temperature and air stability have been fabricated. [27][28][29][30][31] However, owing to the lack of effective doping, Fermi level pinning(FLP) occurs when the metal and the material are in direct contact, resulting in a Schottky barrier at the interface that hinders carrier transport.…”