Atomic layer deposition growth of SnS2 films on diluted buffered oxide etchant solution-treated substrate

Abstract

In this report, two types of substrates were prepared for deposition of few-layer tin disulfide (SnS2) via atomic layer deposition (ALD). The first substrate was prepared using a conventional cleaning method, while the second substrate was rinsed with buffered oxide etcher (BOE) solution after conventional cleaning. Changes in the substrate were confirmed by X-ray photoelectron spectroscopy, contact angle measurements, and electron spin resonance. Characteristics of the SnS2 thin films were determined by X-ray diffraction, Raman analysis, Fourier transform-infrared spectroscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. To investigate growth rate, thickness was measured as a function of ALD cycle number by atomic force microscopy, and 2D layered structure was confirmed by transmission electron microscopy. Findings confirmed that surface treatment using BOE solution was related to an increased growth rate during the initial ALD process. Finally, back-gate field effect transistors based on ALD-grown SnS2 film prepared on substrate that received diluted-BOE surface treatment showed marginal improvement in current on/off ratio from 2.9 × 105 to 6.5 × 105 and mobility from 0.22 cm2/Vs to 0.31 cm2/Vs compared to ALD-grown SnS2 film prepared on bare substrate.