Electrical and dielectric parameters in TiO₂-NW/Ge-NW heterostructure MOS device synthesized by glancing angle...

This paper reports the catalyst-free coaxial TiO₂/Ge-nanowire (NW) heterostructure synthesis using the glancing angle deposition (GLAD) technique integrated into an electron beam evaporator. The frequency and voltage dependence of the capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics of an Ag/TiO₂-NW/Ge-NW/Si device over a wide range of frequency (10 kHz-5 MHz) and voltage (- 5 V to + 5 V) at room temperature were investigated. The study established strong dependence on the applied frequency and voltage bias. Both C-V and G/ω-V values showed wide dispersion in depletion region due to interface defect states (D_it) and series resistance (R_s). The C and G/ω value decreases with an increase in applied frequency. The voltage and frequency-dependent D_it and R_s were calculated from the Hill-Coleman and Nicollian-Brews methods, respectively. It is observed that the overall D_it and R_s for the device decrease with an increase in the frequency at different voltages. The dielectric properties such as dielectric constant ([Formula: see text]'), loss ([Formula: see text]″) and loss tangent (tan δ) were determined from the C-V and G/ω-V measurements. It is observed that [Formula: see text]', [Formula: see text]″ decreases with the increase in frequency. Therefore, the proposed MOS structure provides a promising alternative approach to enhance the device capability in the opto-electronics industry.