Atomic layer deposition of Pt nanoparticles using dimethyl (N, N-dimethyl-3-butene-1-amine-N) platinum and H₂ reactant and its application to 2D WS₂ photodetectors

2D transition metal dichalcogenides (2D TMDCs) have thin and flexible structures and can be widely applied to nanoelectronics technology as a representative of 2D materials. Research studies on the surface functionalization of 2D TMDCs with nanoparticles have been actively conducted for fabrication of high-performance devices. Specifically, platinum (Pt) has attracted significant attention as a surface functionalization material in various applications, including photosensors, biosensors, and gas sensors due to its effective catalytic effect and excellent corrosion resistance. However, solution-based methods and PVD technologies, widely used for Pt nanoparticle synthesis, have difficulties forming fine particles dispersed on nanomaterials. Atomic layer deposition (ALD) is emerging as an advantageous method for forming nanoparticles, and dimethyl (N,N-dimethyl-3-buten-1-amine-N) platinum (DDAP) can overcome disadvantages of conventional ALD Pt precursors. In this study, we successfully synthesized Pt films using hydrogen as a new reactant in the DDAP-based ALD Pt process and evaluated formation of nanoparticles on SiO2/Si substrates. Subsequently, the ALD Pt-functionalized photodetector was fabricated with 2D WS2, a representative visible-light photodetector material, and improvement of photocurrent was confirmed by providing additional carriers via the localized surface plasmon resonance phenomenon. Furthermore, preferentially growing at high surface energy points, such as defects on WS2 nanosheets, can suppress the capture of photoexcited electrons by defects, consequently extending the carrier lifetime and preventing surface oxidation of the device. In the wavelength range of 500-1200 nm, the photoresponsivity of the ALD Pt-functionalized WS2 photodetector was improved more than 10-20 times compared to pristine WS2, and the response time was also noticeably improved. This study presents a novel approach to Pt functionalization using ALD, opening new possibilities for advanced nanodevice applications.