Control Possibilities of Electric Conductivity in Spinel Zinc Gallate, ZnGa2O4

Author: Tsotne Gamsakhurdashvili
Keywords: Ultra-wide bandgap oxide, ZnGa2O4, conductivity, point defects
Annotation:

In the presented work we investigate the possibilities of controlling conductivity type in spinel zinc gallate, ZnGa2O4. ZnGa2O4 is the ternary ultra-wide bandgap oxide semiconductor with the largest bandgap (~5eV), making this material very promising for implementations in deep UV optoelectronics and ultra-high power electronics. In order to investigate the possibilities of controlling conductivity, which is the concentration of charge carriers, we performed the thermodynamic analyses of concentration equilibrium of charge carriers and point defects. The thermodynamic equilibrium in the ZnGa2O4 (crystal) - O2 (gas) system was modeled by the Kroger method of quasi-chemical equations. In this method, the creation of dominant defects and charge carriers are written as chemical reactions. The corresponding mass action laws, together with the electro-neutrality condition and impurity mass balance equation, give a system of equations for the concentrations of the main charged species (acceptor and donor defects, electrons and holes), as well as concentrations of vacant sites and anti-site defects, existing in the crystal. Alongside bulk crystal case, we also investigated thin films case, in which quantum effects are important. We corrected the activation energies in the defect concentration equations and performed the same calculations.

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