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We have investigated the p-dopant potential of 14 different impurities (Be, B, F, Mg, Al,Ca, Sc, Cu, Zn, Ga, In, Ba, Pt, and Tl) within 4H-SiC via Density Functional Theory (DFT) calcu-lations using a hybrid density functional. We analyse the incorporation energies of impurity atomson Si and C sites as well as the character of lattice distortion induced by impurities. The calculatedthermal ionization energies confirm that Al and Ga on the Si site are the best candidates for p-dopingof 4H-SiC. Although we find some correlation of incorporation energies with atomic radii of impuri-ties, the difference in chemical interaction with neighbouring atoms and strong lattice distortions playimportant roles in determining the impurity incorporation energies and charge transition levels. Wefind Al to still be the best and most industrially viable p-dopant for 4H-SiC.

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Switching a silicon carbide (SiC) metal–oxide–semiconductor field-effect transistor between inversion and accumulation with removed drain and grounded source terminals leads to defect-assisted carrier recombination and light emission. The energy spectrum of the emitted photons provides valuable information on the involved defects, located both at the 4H-SiC/SiO2 interface and in the 4H-SiC bulk. Here, we measured and analyzed the emitted light over a broad temperature range between 12 and 297 K. Our results reveal two local maxima in light intensity around 30 and 140 K. Most importantly, the local intensity maxima and the related temperatures correlate with both the overall recombination current and gate capacitance measurements. The spectral analysis allowed us to distinguish between recombinations occurring on 4H-SiC bulk defects and 4H-SiC/SiO2 interface-related defects. We explain an initial increase of light emission with decreasing temperature to competing non-radiative pathways with activation energies of 34 and 60 meV for SiC/SiO2 interface- and 4H-SiC bulk-related emissions, respectively. Based on an extensive literature review, we link the measured photon emission to donor–acceptor pair recombination, the EH6/7 or the Z1/2 defect centers. In addition to that, we could link a prominent peak at 2.915 eV to the L1 line of the D1-center. Most importantly, we conducted our own ab initio simulations revealing that recombination via PbC-centers, previously identified with carbon dangling bonds at the 4H-SiC/SiO2 interface [Cottom et al., J. Appl. Phys. 124, 045302 (2018)], could also provide an explanation for the photon emission around 1.75 eV. Finally, our simulation of an interface-related silicon vacancy VSi,I reveals a radiative transition around 2.8 eV.