Heterostructure Device Based on Graphene Oxide/TiO2/n-Si for Optoelectronic Applications

Abstract

We produced a graphene oxide with good conductivity by a novel method that saves cost and time as illustrated in the structure Au/GO/TiO₂/Si/Al. The GO was synthesized by burning polyvinyl alcohol at 300 °C on the TiO₂/n-Si surface producing a conductive graphene oxide that is considered a new advantage of this technique. The Au/GO/TiO₂/n-Si/Al structure is manufactured using the spin coating process. The XRD and SEM identified the samples’ structure and surface topography. In a frequency range from 10 kHz to 20 MHz, the electrical and dielectric parameters of the synthetic Schottky diodes were obtained from capacitance/conductance-voltage. The diagram of real and imaginary parts of the impedance (Z′, Z″), col-col, and their variation with temperatures, voltage, and frequency were also discussed. A comparison of electrical parameters such as ideality factor (n), series resistance (R_s), barrier height (Φ_b) based on traditional, Cheung, and Norde methods was investigated. The oxide layer thickness values (d_ox), the density distribution (N_ss), the maximum admittance (Y_m), the maximum electric field (E_m), the depletion layer width (W_d), and ΔΦ_b (eV) were investigated using the C² − V relationship. As the frequency increases, the Φ_b(C−V) increases, while the concentration of donor atoms (N_D) decreases. The surface states (N_ss) voltage-dependent profile was calculated and evaluated.