Investigation of structural and dielectric properties of ZnO nanorods growth by hydrothermal method

Zinc oxide (ZnO) nanostructures is a significant material for optoelectronic and sensor devices due to the increasing demand for small-size fabrication of electronic devices in the industry. This thesis is an in-depth investigation of growth and physical properties of the ZnO nanorods (NRs) grown on glass and p-Si substrates. The structural properties and frequency-dependent dielectric function of the In/ZnO/p-Si heterostructures are also investigated. The NRs were produced by hydrothermal method on the substrates in a Teflon-lined stainless-steel cover at 90°C. Scanning electron microscopy analysis indicates nanorod morphology while LeBail refinement of XRD data showed that the ZnO NRs crystallize in hexagonal wurtzile structure with (002) orientation (space group P63mc). The dielectric properties of the In/ZnO/p-Si heterostructure were calculated with the help of experimental admittance measurements performed in the ±5 V voltage range and 1 kHz/1 MHz frequency range under ambient conditions. The real part of the complex relative permittivity (ε′), the imaginary part of complex relative permittivity (ε″) and loss tangent (tanδ) were obtained. Also, real (M′) and imaginary (M″) parts of the complex electric modulus (M*) were extracted. Frequency dependence in the ε′, ε″ and tanδ was attributed to the frequency dependence of the space charge polarization. The real part of electrical modulus was found to be nearly independent of frequency and voltage for positive voltages.