Hybrid DFT of electronic and vibrational properties of irondoped Β-GA2O3 crystals

Abstract

This paper presents the results of calculations of energy and electron-optical
properties of iron-doped β-Ga2O3. By analyzing the arrangement of the electronic levels of the
impurity in the band gap for different charge states, it is shown that Fe is an acceptor impurity.
Evaluation of both optical and thermodynamic transition levels indicates the deep nature of the
iron acceptor impurity. In addition, iron can play the role of a donor at very low Fermi energies,
but the probability of forming such a state is extremely low. We find that iron modifies Raman
scattering in an ambiguous manner. Due to the low effective atomic mass of the substituted
iron atom, doping leads to a pronounced enhancement of phonon modes of vibrations in the
high-frequency range (~ 600÷800 cm-1). The results obtained are in good agreement with
experimental observations, confirming the acceptor character of the iron impurity.