C-Tng Kuo, Q-H Gong, R-Y Pan, H-C Wang
National Sun Yat-sen University,
Taiwan
Keywords: heterostructure, photoelectrochemical, Cu2O, MoS2, photo-response
Summary:
Abstract- In this study, chemical vapor deposition (CVD) was used to grow the MoS2 thin films, and electrochemical deposition was used to grow the Cu2O thin films. We applied mechanical grinding to polishing the surface of the grown Cu2O and made the first treatment of the grown MoS2. Then we transferred MoS2 to Cu2O which had been polished to complete our heterostructure. The analysis of the transmission electron microscopy (TEM) is used to observe the crystal structure of the MoS2 flakes. By observing periodicity diffraction points from the corresponding selected area diffraction pattern (SAD) on Cu2O thin film indicates the monocrystalline with our grown sample. In addition, the measurements of Raman spectroscopy, Multiphoton excitation microscope, Atomic force microscope (AFM) and Photoluminescence (PL), we will able to confirm the monolayer structure of the MoS2 flakes. After preliminary processing of the grown MoS2 flakes, the sample transfer to a Cu2O thin film to complete the p-n heterojunction structure. We analyzed the luminous energygap of the p-n heterojunction structure by using the measurements of Scanning electron microscope (SEM), Second-harmonic generation (SHG), and Raman mapping. It showed that Cu2O thin film prepared by the deposition environment pH value 12 had a highly regular crystallinity and its crystal lattice is complete, while MoS2 is a single-layer structure. Subsequently, we measured the biosensor through the UV-Visible spectrometer and the micro-current meter. Through the steps of the above process, we successfully manufactured a photoelectrochemical biosensor. We used it for photo-response measurement of two cancer cells with different stages of cancerization. Then we obtained the photo-response characteristics and the working wavelength range of our biosensor. In this cancer cell measurement experiments, the characteristic response of biochips to cancer cells and the different cancerous staging characteristics were verified.