Conducting Si-doped γ-Ga2O3 epitaxial films grown by pulsed-laser deposition

• Single crystalline metastable γ-Ga2O3 films were stabilized on MgAl2O4 substrate by pulsed-laser deposition.
• N-type impurity doping for γ-Ga2O3 was achieved using Si as a donor.
• The carrier concentration of highly doped γ-Ga2O3 film was as high as those of α- and β-Ga2O3.

We report structural, electrical, and optical properties of Si-doped γ-Ga2O3 films epitaxially grown on (100) MgAl2O4 substrate by pulsed-laser deposition. The γ-Ga2O3:Si films of a metastable spinel phase had neither secondary phase nor rotation domain. A highly doped film exhibited n-type conductivity with a carrier concentration of 1.8×1019 cm−3 and a Hall mobility of 1.6 cm2 V−1 s−1 at 300 K. Donor activation energy was estimated to be less than 7 meV from nearly temperature-independent transport properties down to 77 K. The successful impurity doping indicates that γ-Ga2O3 can be used as an n-type wide-band-gap semiconductor.