Illumination and Voltage Dependence of Electrical Characteristics of Au/0.03 Graphene-Doped PVA/n-Si Structures via Capacitance/Conductance–Voltage Measurements
SAHAR Alialy1, AHMET Kaya2**, İ Uslu3, ŞEMSETTIN Altındal1
1Physics Department, Faculty of Sciences, Gazi University, Ankara 06500, Turkey 2Opticianry Department, Vocat Sch Med Sci, Turkey Turgut ?zal University, Ankara 78050, Turkey 3Department of Chemistry Education, Faculty of Education, Gazi University, Ankara 06500, Turkey
Abstract：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/ω–V) measurements at room temperature and at 1 MHz. Some of the main electrical parameters such as concentration of doping atoms (ND), barrier height (?B(C?V)), depletion layer width (WD) and series resistance (Rs) show fairly large illumination dispersion. The voltage-dependent profile of surface states (Nss) and resistance of the structure (Ri) are also obtained by using the dark-illumination capacitance (Cdark–Cill) and Nicollian–Brews methods, respectively. For a clear observation of changes in electrical parameters with illumination, the values of ND, WD, ?B(C?V) and Rs are drawn as a function of illumination intensity. The values of ND and WD change almost linearly with illumination intensity. On the other hand, Rs decreases almost exponentially with increasing illumination intensity whereas ?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.
2015, Vol. 32 
