Illumination and Voltage Dependence of Electrical Characteristics of Au/0.03 Graphene-Doped PVA/n-Si Structures via Capacitance/Conductance-Voltage Measurements

Sahar A., Ahmet K., Uslu I., Semsettin A.

CHINESE PHYSICS LETTERS, vol.32, no.11, 2015 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 32 Issue: 11
  • Publication Date: 2015
  • Doi Number: 10.1088/0256-307x/32/11/116102
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Gazi University Affiliated: Yes


Au/n-Si (MS) structures with a high dielectric interlayer (0.03 graphene-doped PVA) are fabricated to investigate the illumination and voltage effects on electrical and dielectric properties by using capacitance-voltage (C - V)and conductance-voltage (G/omega-V) measurements at room temperature and at 1 MHz. Some of the main electrical parameters such as concentration of doping atoms (N-D), barrier height (Phi(B)(C - V)), depletion layer width (W-D) and series resistance (R-s) show fairly large illumination dispersion. The voltage-dependent profile of surface states (N-ss) and resistance of the structure (R-i) are also obtained by using the dark-illumination capacitance (C-dark - C-ill) and Nicollian-Brews methods, respectively. For a clear observation of changes in electrical parameters with illumination, the values of N-D, W-D, Phi(B)(C - V) and R-s are drawn as a function of illumination intensity. The values of N-D and W-D change almost linearly with illumination intensity. On the other hand, R-s decreases almost exponentially with increasing illumination intensity whereas Phi(B)(C - V) increases. The experimental results suggest that the use of a high dielectric interlayer (0.03 graphene-doped PVA) considerably passivates or reduces the magnitude of the surface states. The large change or dispersion in main electrical parameters can be attributed to generation of electron-hole pairs in the junction under illumination and to a good light absorption. All of these experimental results confirm that the fabricated Au/0.03 graphene-doped PVA/n-Si structure can be used as a photodiode or a capacitor in optoelectronic applications.