Optical and electrical properties of two-dimensional palladium diselenide

Abstract

Two-dimensional (2D) noble-metal dichalcogenides exhibit exceptionally strong thickness-dependent bandgaps, which can be leveraged in a wide variety of device applications. A detailed study of their optical (e.g., optical bandgaps) and electrical properties (e.g., mobilities) is important in determining potential future applications of these materials. In this work, we perform detailed optical and electrical characterization of 2D PdSe 2 nanoflakes mechanically exfoliated from a single-crystalline source. Layer-dependent bandgap analysis from optical absorption results indicates that this material is an indirect semiconductor with bandgaps of approximately 1.37 and 0.50 eV for the monolayer and bulk, respectively. Spectral photoresponse measurements further confirm these bandgap values. Moreover, temperature-dependent electrical measurements of a 6.8-nm-thick PdSe 2 flake-based transistor show effective electron mobilities of 130 and 520 cm 2 V À1 s À1 at 300 K and 77 K, respectively. Finally, we demonstrate that PdSe 2 can be utilized for shortwave infrared photodetectors. A room-temperature specific detectivity (D Ã) of 1.8 Â 10 10 cm Hz 1/2 W À1 at 1 lm with a band edge at 1.94 lm is achieved on a 6.8-nm-thick PdSe 2 flake-based photodetector.

Two‐Dimensional Noble‐Metal Chalcogenides and Phosphochalcogenides

“…clearly proved 9 nm thick 2 O ‐PdSe 2 to be a semiconductor by integrating it into a FET and showing that the band gap could be closed by an external electric field. Zhang et al . measured a band gap of 0.5 eV for bulk PdSe 2 .…”

“…measured a bilayer band gap in the range of 1.15–1.35 eV, with the gap depending on the growth substrate as a result of the proximity screening effect . In monolayers, a band gap of 1.37 eV was measured . This is in line with our hybrid functional calculations, where we predict an increase in the band gap from 0.96 eV for the bulk phase to 1.8 eV for the bilayer and to 2.3 eV for the monolayer (Figure c and Figures S17 and S18).…”

Evaporated SexTe1‐x Thin Films with Tunable Bandgaps for Short‐Wave Infrared Photodetectors

“…Surface recombination is therefore small by comparison to conventional 3D crystals (such as Ge, InGaAs, and InGaAsP) [ 5–7 ] and layered 2D crystals (such as black phosphorous, PtSe 2 and PdSe 2 ). [ 28–31 ]…”

Zweidimensionale Edelmetallchalkogenide und ‐phosphochalkogenide

“…eindeutig, dass 9 nm dickes 2 O ‐PdSe 2 halbleitend ist, indem die Autoren es in einen FET integrierten, und dass die Bandlücke mit einem externen elektrischen Feld geschlossen werden kann. Zhang et al . haben eine Bandlücke von 0.5 eV in Bulk‐PdSe 2 gemessen.…”

“…haben eine Bandlücke in Bilagen im Bereich von 1.15–1.35 eV gefunden, die vom Substrat durch Abschirmungseffekte abhängt . In Monolagen wurde eine Bandlücke von 1.37 eV bestimmt …”