Tuning electrical conductivity of β-Ga2O3 single crystals by Ta doping

Ta-doped β-Ga2O3 single crystals were grown to regulate the electrical properties of β-Ga2O3. The carrier concentration is intentionally controllable, and can be defined from 3.6 × 1016 cm−3 to 3.0 × 1019 cm−3, by controlling Ta concentration. The optical transmittance of Ta-doped single crystals was as high as 70%–80% in the visible region. In addition, it distinguished by a decline trend in the IR region, which attributed to the increase of the carrier concentration with Ta doping. Raman spectra revealed that the intensity and the FWHM of GaO6 octahedra peaks increased with increasing Ta content. DLTS showed only one deep level defect at 0.73 eV below the conduction band, and this defect had little contribution to the carrier concentration.