Analysis of temperature-dependent electrical resistivity of ZnO nano-structures

Abstract

The temperature–dependent electrical resistivity ρ( T) in metallic and semiconducting phase of ZnO nanostructures is theoretically analysed. ρ( T) shows semiconducting phase in low temperature regime (140 K< T<180 K), shows an absolute minimum near 180 K and increases linearly with T at high temperatures (200 K< T<300 K). The resistivity in metallic phase is estimated within the framework of electron–phonon and electron–electron scattering mechanism. The contributions to the resistivity by inherent acoustic phonons ( ρ ac) as well as high frequency optical phonons ( ρ op) were estimated using Bloch–Gruneisen (BG) model of resistivity. The electron–electron contributions ρ e− e = BT 2 in addition with electron–phonon scattering is also estimated for complete understanding of resistivity in metallic phase. Estimated contribution to resistivity by considering both phonons, i.e., ω ac and ω op and the zero limited resistivity are added with electron–electron interaction ρ e–e to obtain the total resistivity. Resistivity in Semiconducting phase is discussed with small polaron conduction (SPC) model. The SPC model consistently retraces the low temperature resistivity behaviour (140 K< T<180 K). Finally the theoretically calculated resistivity is compared with experimental data which appears favourable with the present analysis in wide temperature range.