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.