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Publication Discovering semiconductors for power electronics through first-principles computations(Colorado School of Mines. Arthur Lakes Library, 2024)To support renewable energy and widespread electrification, power electronics must efficiently convert power at high operating voltage and switching frequency, within a compact size. State-of-the-art SiC and GaN wide bandgap semiconductor devices cannot meet all future demands. Ultrawide bandgap alternatives theoretically improve conversion performance but are difficult to grow as large single crystals (c-BN, diamond, AlN), have low thermal conductivity (Ga$_2$O$_3$), or cannot be suitably doped (AlN, p-type Ga$_2$O$_3$). This dissertation identifies new semiconductors for power electronics using first-principles DFT calculations. I begin with high-throughput screenings across $\approx$1300 known crystals. The first study screens for alternatives to SiC for high-power devices and the second for alternatives to GaN for high-switching frequency. Candidates are ranked by figures of merit (i.e. Baliga, Johnson) and thermal conductivity ($\kappa_L$), using models to describe transport properties. I identify 47 high-power and 20 high-switching frequency candidates with better n-type figures of merit than SiC and GaN and larger $\kappa_L$ than Ga$_2$O$_3$. Next, I evaluate candidate dopability. The branch point energy is used to rank the likelihood of successful n-type doping to prioritize candidates for subsequent modern defect calculations. Among a group of calcite-type borates, defect calculations predict InBO$_3$ has the most potential for n-type doping without compensation by native acceptors. Furthermore, zirconium is predicted to readily substitute for In and behave as a shallow donor with maximal net donor concentrations exceeding $10^{18}$ cm$^{-3}$ under typical growth conditions. Thortveitite and pyrochlore In$_2$Ge$_2$O$_7$ and In$_2$Si$_2$O$_7$ are also predicted to be dopable with Zr with net donor concentrations of $10^{15}$ to above $10^{21}$ cm$^{-3}$. Conversely, native defect formation energies for spinels Mg$_2$GeO$_4$ and Al$_2$ZnO$_4$ indicate compensation by cation antisites. From this work, I propose InBO$_3$, In$_2$Ge$_2$O$_7$, and In$_2$Si$_2$O$_7$ for n-type high-power or high switching-frequency electronics. Given the proposed chemistries, I address concerns for indium mineral criticality. Using supply chain data, I estimate that the future indium demand for power electronics will consume less than 10% of supply. Therefore, indium-based power electronics are not predicted to be a large burden on supply, especially compared to competing technologies, and their existence may alleviate supply pressures of SiC and GaN. This work successfully identifies materials that are potentially better alternatives to SiC and GaN for future power electronics. If commercialized, these semiconductors will enable increased operating limits, more efficient conversion, and flexible control of power, leading to a more renewable and electrified world.Publication Publication Publication Publication