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Tunable Current Transport in PdSe 2 via Layer‐by‐Layer Thickness Modulation by Mild Plasma
Author(s) -
Das Tanmoy,
Seo Dongwook,
Seo Jae Eun,
Chang Jiwon
Publication year - 2020
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202000008
Subject(s) - materials science , optoelectronics , etching (microfabrication) , raman spectroscopy , plasma , layer (electronics) , plasma etching , reactive ion etching , nanotechnology , heterojunction , field effect transistor , transistor , optics , voltage , electrical engineering , physics , quantum mechanics , engineering
The thickness‐modulated phase transition from semi‐metallic (bulk) to semiconductor (a few layers) is the most unique property of pentagonal palladium diselenide (PdSe 2 ). Thus, precise thickness tailoring is essential to fully utilize its unique thickness‐dependent property for exotic device applications. Here, tunable current transport in PdSe 2 based field‐effect transistors (FETs) enabled by layer‐by‐layer thinning of PdSe 2 using mild SF 6 :N 2 plasma is presented. With this top‐down plasma‐etching method, the PdSe 2 layer thickness can be precisely modulated without structural degradation, which paves the way to realize the complete potential of PdSe 2 ‐based devices. By modifying the plasma power and exposure time, an atomic layer precision etching rate of 0.4 nm min −1 can be achieved. Atomic‐force microscopy, Raman spectroscopy, and secondary ion mass spectrometry confirm the uniform and complete removal of top layers of PdSe 2 flake over a large area without affecting remaining bottom layers. Electrical characterization of current transport in plasma‐thinned PdSe 2 FETs reveals excellent layer‐dependent conductivity similar to pristine PdSe 2 FETs. This simple but highly scalable and controllable plasma‐etching technique provides a promising way to fabricate PdSe 2 devices based on lateral heterostructures composed of different thicknesses PdSe 2 flakes to exploit strongly thickness‐dependent electronic structures.