Evaluation of Sn-doped <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>β</mml:mi> <mml:mo>−</mml:mo> </mml:mrow> </mml:math> Ga₂O₃ persistent photoconductivity with sub-band gap excitation energy

Abstract Beta-gallium oxide ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>β</mml:mi> <mml:mo>−</mml:mo> </mml:mrow> </mml:math> Ga 2 O 3 ) is positioned as an ultra-wide bandgap semiconductor for optoelectronic and electronic applications under extreme conditions. However, its characterization is not easy to achieve. Even the standard Hall technique is difficult to implement due to the low conductivity of the samples compared to ohmic contacts. In this work, we propose an evaluation of a Sn-doped <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>β</mml:mi> <mml:mo>−</mml:mo> </mml:mrow> </mml:math> Ga 2 O 3 sample based on photoconductivity measurements with sub-band gap 280 nm excitation. The sample shows a persistent photoconductivity with an irregular behavior. The procedure used is based on a dynamical model of charge transport in semiconductors. Relevant parameters are estimated by fitting theoretical predictions obtained from the model to experimental photoresponse curves. We obtain values for electron and hole mobilities, Sn doping and defect concentrations. In addition, the proposed method allows to evaluate the charge exchange between bands and defects during the measurements which allows to explain the observed behavior.