Structure and vibrational properties of the dominant O-H center in β-Ga2O3

Abstract

Hydrogen has a strong influence on the electrical properties of transparent conducting oxides where it can give rise to shallow donors and can passivate deep compensating defects. We have carried out infrared absorption experiments on H- and D-doped β-Ga2O3 that involve temperature- and polarization-dependent effects as well as relative H- and D-concentrations to probe the defect structures that hydrogen can form. The results of analysis of these data, coupled with detailed theoretical calculations, show that the dominant O-H vibrational line observed at 3437 cm−1 for hydrogenated Ga2O3 is due to a relaxed VGa-2H center.

Impact of deep level defects induced by high energy neutron radiation in β-Ga2O3

“…To date, there have been several theoretical calculations predicting energy levels for acceptor-like gallium vacancies and donor-like oxygen vacancies that are close to the experimentally observed deep levels here. [35][36][37][38][39] Hydrogen-gallium vacancy complexes (i.e., V Ga -H, V Ga -2H) might also play a role since irradiation can affect the degree of H saturation of V Ga with different charge state transitions, (0/−1), (−1/−2), (−2/−3), etc., which has also been reported for proton-implanted β-Ga 2 O 3 with the V Ga -2H complex formation, 44 and possibly cause Frenkel pair generation. 39,45 Regarding the E C −4.48 eV state that remained unaffected after irradiation for both doses, this energy level is close to those that have been predicted for vacancies; 38,46 however, Note that the concentrations of the DLOS traps before and after irradiation are likely even greater (but at same ratio) than shown here due to their small optical cross sections causing an underestimation of these values.…”

Unusual Formation of Point-Defect Complexes in the Ultrawide-Band-Gap Semiconductor β−Ga2O3

“…[19,21]. These DFT results have also been utilized in recent β-Ga2O3 defect studies using electron spin resonance [37,38] and infrared spectroscopy [39,40] to attribute the presence of proton irradiation induced defects and implanted O-H bonds to the same point defect complexes.…”

Hydrogen plasma treatment of β -Ga2O3: Changes in electrical properties and deep trap spectra

“…8-12 IR absorption peaks observed at 3437 cm À1 in annealed samples by Weiser et al 10 are attributed to a gallium vacancy decorated with two hydrogen atoms. Ritter et al 12 demonstrated that hydrogen-annealing of Ga 2 O 3 :Mg produced an IR peak at 3492 cm À1 , assigned to an O-H bond-stretching mode of a neutral MgH complex.…”