Large area growth of layered WSe2 films

Abstract

Growth of smooth and continuous films of WSe2 has been demonstrated by employing atomic layer deposition (ALD) on 5 cm × 5 cm substrates. The substrates consisted of silicon wafers with a layer of SiO2. The ALD precursors were WCl5 and H2Se. The film properties characterized using Raman spectroscopy and x-ray photoelectron spectroscopy are comparable to those reported for WSe2 films produced by chemical vapor deposition and exfoliation. Carrier mobilities were determined with back-gated transistors. With Pd contacts, median electron and hole mobilities of 531 cm2 V−1 s−1 and 354 cm2 V−1 s−1, respectively, were measured.