Large Area Vertically Oriented Few-Layer MoS₂ for Efficient Thermal Conduction and Optoelectronic Applications

Large area growth of MoS₂ can show great advances in optoelectronic devices due to its unique optical and electronic properties. Here, we directly grow vertically oriented and interconnected few-layer MoS₂ over 1 × 1 cm² of p-type Si substrate using CVD technique. We report for the first time the thermal conductivity of vertically oriented few-layer (VFL) MoS₂ using the optothermal Raman technique. The reduced phonon-defect scattering due to minimal defects and strains in VFL MoS₂ results in excellent thermal conductivity of 100 ± 14 W m^-1 K^-1 at room temperature. The photoluminescence and DFT study confirm the semiconducting behavior of VFL-MoS₂. The VFL-MoS₂/Si photodiode shows high photoresponsivity of 7.37 A W^-1 at -2.0 V bias under 0.15 mW cm^-2 intensity of 532 nm laser. The enhanced light trapping and highly exposed edges of VFL MoS₂ due to vertical orientation, formation of efficient p-n junction at the MoS₂/Si interface and effective charge separation leads to the excellent performance of grown VFL-MoS₂ for optoelectronic applications.