Assignments of vibrational lines to OD-impurity complexes for adventitious impurities in β-Ga2O3.

Hydrogen in β-Ga₂O₃ passivates shallow impurities and deep-level defects and can have a strong effect on conductivity. More than a dozen O–D vibrational lines have been reported for β-Ga₂O₃ treated with the heavy isotope of hydrogen, deuterium. To explain the large number of O–D centers that have been observed, the involvement of additional nearby defects and impurities has been proposed. A few O–H centers have been associated with specific impurities that were introduced intentionally during crystal growth. However, definitive assignments of O–H and O–D vibrational lines associated with important adventitious impurities, such as Si and Fe, have been difficult. A set of well-characterized Si-doped β-Ga₂O₃ epitaxial layers with different layer thicknesses has been deuterated and investigated by vibrational spectroscopy to provide new evidence for the assignment of a line at 2577 cm⁻¹ to an OD–Si complex. The vibrational properties of several of the reported OD-impurity complexes are consistent with the existence of a family of defects with a V Ga 1 ic − D center at their core that is perturbed by a nearby impurity. [ABSTRACT FROM AUTHOR]