Ga2O3 films for electronic and optoelectronic applications

Abstract

Properties of Ga2O3 thin films deposited by electron-beam evaporation from a high-purity single-crystal Gd3Ga5O12 source are reported. As-deposited Ga2O3 films are amorphous, stoichiometric, and homogeneous. Excellent uniformity in thickness and refractive index was obtained over a 2 in. wafer. The films maintain their integrity during annealing up to 800 and 1200 °C on GaAs and Si substrates, respectively. Optical properties including refractive index (n=1.84–1.88 at 980 nm wavelength) and band gap (4.4 eV) are close or identical, respectively, to Ga2O3 bulk properties. Reflectivities as low as 10−5 for Ga2O3/GaAs structures and a small absorption coefficient (≊100 cm−1 at 980 nm) were measured. Dielectric properties include a static dielectric constant between 9.9 and 10.2, which is identical to bulk Ga2O3, and electric breakdown fields up to 3.6 MV/cm. The Ga2O3/GaAs interface demonstrated a significantly higher photoluminescence intensity and thus a lower surface recombination velocity as compared to Al2O3/GaAs structures.

Light-emitting Ga-oxide nanocrystals in glass: a new paradigm for low-cost and robust UV-to-visible solar-blind converters and UV emitters

“…The reported E G values in Ga 2 O 3 phases, mainly from measurements of the optical absorption edge of thin lms, lie in the range from 4.2 to 5.1 eV. [43][44][45][46][47][48][49][50][51] Such a spread of values is related to the variability of oxygen stoichiometry in Ga-oxides, the larger the oxygen de-ciency, the smaller the effective bandgap. 32 Additional spread of E G values can be expected in NCs, in principle, from quantum connement (QC).…”

Influence of Environment on the Measurement of Rates of Charge Transport across AgTS/SAM//Ga2O3/EGaIn Junctions

“…Gallium oxide, formed spontaneously on the surface of the EGaIn electrode, is probably much less structured and more conducting than pure gallium oxide (formed by vapor deposition at high temperatures, 29 thermal annealing, 30 or by epitaxial growth on GaAs 31 ).…”

Lattice dynamics of a mist-chemical vapor deposition-grown corundum-like Ga2O3 single crystal

“…6 The monoclinic b-phase is thermodynamically the most stable phase at ambient conditions. 7 Owing to its unique physical properties, such as chemical and thermal stability at high temperatures, large bandgap (E g ¼ 4.9 eV), large breakdown field (estimated at 8 MV cm À1 ), and high dielectric constant ($10) 8,9 as well as to its widely tunable conductivity, 10 a great effort has been devoted in the past decade to the development of b-Ga 2 O 3 -based device technology. Ga 2 O 3 is a promising material to realize low-cost power devices outperforming those based on GaN or SiC.…”