On demand generation of photoluminescence on thick MoS$_{\mathrm{2}}$ flakes via laser thinning and gold nanoparticle self-assembly

Recently, the photoluminescence (PL) property of monolayer and few layer transition metal dichalcogenides (TMDs) has aroused tremendous attention. However, the difficulty in synthesizing large area monolayer and few layer TMDs limits its application. Here we show that photoluminescent patterns with arbitrary shapes can be produced via a simple but effective method based on thick MoS$_{\mathrm{2}}$ flakes. By scanning focused laser beam on thick MoS$_{\mathrm{2}}$ flakes, few layer MoS$_{\mathrm{2}}$ and thick edges can be fabricated arbitrarily. After the laser treated MoS$_{\mathrm{2}}$ being immersed in AuCl$_{\mathrm{3}}$ solution, gold nanoparticles are selectively grown on the few layer MoS$_{\mathrm{2}}$ and thick edges where the particle size on edges (from 100nm to 400nm) are much larger than that on few layer MoS$_{\mathrm{2}}$ (less than 150nm) The obtained PL spectra show that the PL intensity is largely enhanced (up to 20 fold) and an obvious blue shift can be observed after the gold growth. We also demonstrate that arbitrary fluorescent patterns can be produced by this laser thinning and gold deposition process.