2021/05/07 by Lei Zhang, Zhang, Lei, Tong Yang +16
Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #cond-mat.mtrl-sci #physics.app-ph
paper · pdf · doi:10.48550/arxiv.2105.03334
arxiv created 2021/05/07 · arxiv updated 2021/05/10
Two-dimensional (2D) platinum diselenide (PtSe2) has received significant attention for 2D transistor applications due to its high mobility. Here, using molecular beam epitaxy, we investigate the growth of 2D PtSe2 on highly oriented pyrolytic graphite (HOPG) and unveil their electronic properties via X-ray photoelectron spectroscopy, Raman spectra, and scanning tunnelling microscopy/spectroscopy as well as density functional theory (DFT) calculations. PtSe2 adopts a layer-by-layer growth mode on HOPG and shows a decreasing band gap with increasing layer number. For the layer numbers from one to four, PtSe2 has band gaps of 2.0 ± 0.1, 1.1 ± 0.1, 0.6 ± 0.1 and 0.20 ± 0.1 eV, respectively, and becomes semimetal from the fifth layer. DFT calculations reproduce the layer-dependent evolution of both the band gap and band edges, suggest an indirect band-gap structure, and elucidate the underlying physics at the atomic level.