Vol.:(0123456789) 1 3 Applied Physics A (2020) 126:475 https://doi.org/10.1007/s00339-020-03650-y Growth dynamics of pulsed laser deposited WS 2 thin flms on diferent substrates Gobinda Pradhan 1  · Partha P. Dey 1  · Ashwini K. Sharma 1 Received: 13 January 2020 / Accepted: 18 May 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract The scaling behavior, as well as growth mechanism of polycrystalline WS 2 thin flms grown on glass and Si substrates by pulsed laser deposition as a function of the deposition time, has been studied using height–height correlation function using the AFM images. X-ray difraction measurement confrms the increase in crystallinity of the WS 2 thin flm on both the sub- strates. The WS 2 flms deposited onto Si substrate showed high rate of roughening or interface width (w) and a rapid increase in island size or correlation length (ξ) of WS 2 nanoclusters in comparison to the flms deposited onto glass substrate. The WS 2 flms grown on glass substrate evolved following the nonlinear stochastic deposition equation, however, WS 2 flms on Si substrate follow a linear growth model. The diference in surface smoothness, thermal conductivity and sticking coef- fcient of the two substrates causes diferent growth patterns of WS 2 flms onto the substrates. The growth of the WS 2 flms on the two diferent substrates evolved diferently which has been realized more conveniently by schematically analyzing the behavior of the evolution of ξ and w with deposition time, t. The high roughness of the flms deposited onto oxidized Si provides a large surface area, which will be useful for electro-catalysis applications. Keywords WS 2 thin flms · Pulsed laser deposition · Growth dynamics · Height-height correlation function 1 Introduction Layered transition metal dichalcogenide (TMDC) materials have emerged as a class of two-dimensional (2D) materi- als with excellent electronic and optical properties [1–3]. Among them, WS 2 has drawn tremendous attention due to its attractive properties like thickness dependent bandgap of 1.2 (indirect) to 1.9 (direct) eV, high electron mobility, high electronic on–of switching ratio, efcient photo responsibil- ity, etc. [4–6]. In the last few years, pulsed laser deposited monolayer to multilayered as well as bulk-like WS 2 flms demonstrated their efcient uses as photodetector, catalyst and other advanced electronics and optoelectronic devices [7–9]. Surface morphology of a thin flm does regulate many of the physical and chemical properties which have a sharp impact on the device performance of the respective flms. The growth dynamics of thin flms represented by scaling theory is a useful tool to explain the evolution of the surface morphology of thin flms and to formulate theoretical models of growth modes for diferent organic and inorganic materi- als [10–13]. So the understanding of the growth dynamics of the deposited thin flms is important to develop an optimized thin flm for efcient device performance. However, despite the rapid progress in applications of WS 2 layered flms, there is no such report on scaling behavior and growth dynamics of WS 2 flms. Hence, we undertake a comparative study on the growth evolution of a few layered to bulk-like WS 2 flms on two diferent substrates, in the light of scaling theory and stochastic growth equation. Height-height correlation function (HHCF) is ftted with an appropriate theoretical model to evaluate the interface width (w) and lateral correla- tion length (ξ) of the flms of various deposition time. The surface morphology properties of the flms measured and presented statistically in terms of various scaling exponents like short range (local) as well as long-range (global) rough- ness exponents (  loc and  ), growth exponent (  ), dynamic scaling exponent (1/z), etc. Further, the growth mechanism of the WS 2 flms are compared with the linear and nonlinear stochastic thin flm growth equations. This understanding can enable one to attain controlled growth of a flm required * Ashwini K. Sharma aksharma@iitg.ac.in 1 Department of Physics, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India