Charge Redistribution Mechanisms in SnSe2 Surfaces Exposed to Oxidative and Humid Environments and Their Related Influence on Chemical Sensing

• DOI: 10.1021/acs.jpclett.0c02616
• Publication Date: 2020-10-09T20:45:02Z
• Authors: Gianluca D’Olimpio; Francesca Genuzio; Tevfik Onur Menteş; Valentina Paolucci; Chia-Nung Kuo; Amjad Al Taleb; Chin Shan Lue; Piero Torelli; Daniel Farías; Andrea Locatelli; Danil W. Boukhvalov; Carlo Cantalini; Antonio Politano
• Keywords: Redistribution

Tin diselenide (SnSe2) is a van der Waals semiconductor, which spontaneously forms subnanometric SnO2 skin once exposed to air. Here, by means of surface-science spectroscopies and density functional theory, we have investigated the charge redistribution at SnO2–SnSe2 heterojunction in both oxidative humid environments. Explicitly, find that work function pristine SnSe2 surface increases 0.23 0.40 eV upon exposure O2 air, respectively, with transfer reaching 0.56 e–/SnO2 between underlying skin. Remarkably, defective display chemical inertness toward water, contrast other metal chalcogenides. Conversely, interface formed oxidation highly reactive subsequent implications for SnSe2-based devices working ambient humidity, including sensors. Our findings also imply recent reports on humidity sensing should be reinterpreted, considering pivotal role oxide interaction water molecules.