STUDY OF THE EFFECT OF CARBON DOPING ON MOLYBDENUM DISULFIDE FOR VISIBLE LIGHT PHOTODETECTOR APPLICATIONS

• Main Author: Sarihon Sianturi, Indris
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85113
• Institution: Institut Teknologi Bandung

We study the effect of atomic carbon (C) doping concentrations on the structural, optical, and electrical properties of the thin film molybdenum disulfide (MoS2). Thin films are synthesized using the DC unbalanced magnetron sputtering (DCUBMS) method on n-Si (100) substrate at room temperature. Scanning Electron Microscopy (SEM) characterizes the morphological structure of MoS2 and C-doped MoS2 thin film, showing the expansion of the surface of the thin movie flake on the indicated C-doping MoS2 from the transition of agglomerated flake to wide flake sheets. The XRD spectrum shows that adding C atoms raises the level of hexagonal MoS2 crystallization (2H- MoS2) by widening the distance between MoS2 layers from 5.93 Å to 6.13 Å. This indicates that the C atom is induced between the MoS2 layers that fix the crystalline defect so that the interlayer distance of 2H- MoS2 decreases. The increase in the crystalline degree of C-doped MoS2 is supported by an increase in crystal size and a decrease in dislocation density. Raman's spectroscopy characterized the chemical bonding composition of 2H-MoS2 layered structures and found the presence of an amorphous carbon layer (ACL) indicating carbon interstitial doping on MoS2 interlayer space and the bond between oxygen and Mo forms a molecular bond of molybdenum trioxide (MoO3). Photoluminescence spectroscopy showed a reduction in crystal defects of sulfur vacancy on C-doped MoS2. The passivation of sulfur vacancies improves the optical properties by widening the energy band gap and increasing photon absorption at visible light wavelengths, supported by the presence of exiton A, exiton B, trion, and biexiton exiton bands. We conduct I-V tests to evaluate the performance of C-doped MoS2 metal-semiconductor-metal (MSM) photodetectors in visible light. C-doped MoS2 improved responsivity, specific detectivity, external quantum efficiency (EQE), and reduced Schottky barrier height (SBH) from 0,40 eV menjadi 0,20 eV. C-doped MoS2 thin film has significantly improved the performance of metal-semiconductor-metal (MSM) photodetectors by passivating sulfur vacancies. As a result, functionalized C-doped MoS2 thin film is a promising future strategy for advanced visible-light photodetector devices.