The Research On Two-dimensional Atomic Materials/Semiconductor Heterojunction Optoelectronic Device

Due to the rich and unique physical property, the two-dimensional(2D) atomic materials, like MoS2 and graphene, have important application in electrical and optoelectronic devices.The 2D atomic materials/semiconductor van der Waals heterojunction distinct from traditional p-n junction, as the Fermi level of graphene and MoS2 can be adjusted independently, making it to be the new foundation of the integrated circuit and electronic devices in future. In this thesis, the application of graphene/GaAs and MoS2/GaAs heterojunctions in photodetector and solar cells were investigated. The main contributions in this thesis including:1. Synthesized large area of single-layer graphene and MoS2 through mechanical exfoliation and chemical vapor deposition(CVD) method.2. Sandwiched h-BN as an interlayer in MoS2/GaAs heterojunction to suppress the static charge transfer, then by employing chemical doping, thus, improving the PCE of MoS2/GaAs solar cells from 4.82% to 7.15%.3. Fabricated MoS2/h-BN/GaAs heterojunction self-driven photodetector with quantum dot photo-induced dopant, the responsivity and detectivity become 582 mA/W and 3.2 X 1014cm cm-Hz1/2/W for 635nm incident light, compared with MoS2/GaAs photodetector.4. Fabricated plasma enhanced MoS2/GaAs photodetector, the responsivity was 10.5 A/W for 635nm incident light, which is increase by 20% when compared to the MoS2/GaAs photodetector.5. Fabricated graphene-dielectric-graphene gating structure for graphene/GaAs heterojunction to adjust the Fermi level of graphene,18.5% PCE of graphene/GaAs solar cell was achieved.6. The photodetector of graphene/h-BN/GaAs sandwich structure was fabricated, and its on/off ratio was increased by one magnitude.