Carbon-doped MoS2 for ultraviolet (UV) photodetector device

Pristine molybdenum disulfide (MoS₂) and carbon (C)-doped MoS₂ thin films were synthesized using DC-unbalanced magnetron sputtering on n-Si substrates to study their optical and electrical properties. The pristine MoS₂ thin film exhibits an agglomerated flake structure, whereas carbon-doped MoS₂ form sheet-like flakes. Carbon atoms were detected in the MoS₂ thin film, forming chemical bonds such as S-C and C=C. Carbon-doped MoS₂ enhanced optical absorption and increased the band gap energy from 1.35 eV to 2.12 eV. When pristine MoS₂ and C-doped MoS₂thin films were assembled on metal-semiconductor-metal (MSM) photodetectors with Ag as a metal contact, the MSM formed a Schottky barrier structure. Carbon doping reduced Schottky barrier height (SBH) of MoS₂ from 0.38 eV to 0.27 eV. The I-V characteristic demonstrates the photodetector’s performance under UV light. The responsivity at V_DS = 5 volts increased three times and the detectivity enhanced from 0.78×10¹⁰ Jones to 2.84 ×10¹⁰ Jones after carbon doping is obtained. This study indicates that C-doped MoS₂ can enhance photodetector performance, opening new opportunities for optoelectronic device.