As a promising candidate for next‐generation electronic devices, Ga 2 O 3 still presents challenges, particularly in tailoring its electrical conductivity. In this work, we demonstrate that conductivity in β‐Ga 2 O 3 heteroepitaxial films can be significantly enhanced by modifying donor energy levels through controlled Si doping and indium alloying. Si‐doped Ga 2 O 3 and (In 0.5 Ga 0.5 ) 2 O 3 thin films were grown on c‐plane sapphire substrates using metal‐organic chemical vapor deposition (MOCVD), and their structural, optical, and electrical properties were investigated. A high electron mobility of 126 cm 2 /V s was achieved in Si‐doped β‐Ga 2 O 3 , among the highest reported for heteroepitaxial films on sapphire substrate. Hall‐effect measurements reveal a large increase in carrier concentration and conductivity at the same Si flow rate for (In 0.5 Ga 0.5 ) 2 O 3 despite a mobility reduction to 13.74 cm 2 /V s due to increased scattering. Cryogenic thermally stimulated photoemission spectroscopy (C‐TSPS), developed in‐house, reveals that Si doping in (In 0.5 Ga 0.5 ) 2 O 3 introduces donors with lower ionization energies compared to Si‐doped Ga 2 O 3 . These shifts in donor energy levels explain the enhanced electrical conductivity observed with the Hall measurement. This study offers new insights into defect‐level engineering in β‐Ga 2 O 3 alloys and establishes a novel pathway to optimize electrical performance in Ga 2 O 3 ‐based heterostructures.
Appuhami et al. (Sun,) studied this question.