Dependence of electrical conductivity of -Ga₂O₃ ceramics on oxygen partial pressure and formation of dislocations

The electrical conductivity of porous and high-purity beta-Ga2O3 ceramics was measured as a function of oxygen partial pressure, po(2), at 700 to 900 degrees C. In the high po(2) range, the conductivity was proportional to about -1/4th power of po(2), while in the lower po(2) range less than about 10(-5) atm its exponent was -0.1 to -0.13. This suggests that different types of defects were formed at high and low po(2). The point defect of doubly ionized interstitial gallium ion causes the exponent of -1/4, the same value of the experiment in high po(2). When po(2) was changed, the electrical conductivity first changed sharply, followed by a slow change, suggesting some migrations and/or formation of crystalline defects, and so on. In the Ga2O3 samples, many dislocations, with density of about 10(12) cm(-2), were observed. As the source of carriers, line defects, such as dislocations, should be considered as well as point defects. (C) 2021 The Ceramic Society of Japan. All rights reserved.