Hole Conduction Mechanism in In–Mg-Codoped GaN Prepared via Pulsed Sputtering Deposition

This study reports the pulsed sputtering deposition (PSD) epitaxial growth of In–Mg-codoped GaN with a high hole concentration of 6.2 × 10¹⁸ cm⁻³ and its hole conduction mechanism. X-ray diffraction analysis shows that In–Mg-codoped GaN coherently grows on a GaN substrate without structural degradation and In concentration is 1.3%. Temperature-dependent conductivity is explained by the combination of the band and nearest-neighbor hopping conduction models. Curve fitting in the band conduction region is used to estimate the Mg activation energy, which is as low as 89 meV. This is responsible for the high hole concentration of 6.2 × 10¹⁸ cm⁻³. These results indicate that In–Mg codoping using low-temperature PSD is a promising technique for the preparation of GaN with a high hole concentration without structural degradation.