Fig. 1: Schematic diagrams illustrating the discovery of wide-bandgap (WBG) semiconductors, and a flowchart of the proposed ab initio screening methodology.
a Compared to the 1st and 2nd generation semiconductors (e.g., Si with Eg = 1.1 eV, GaAs with Eg = 1.4 eV), the 3rd generation wide-bandgap (WBG) semiconductors (e.g., 4H-SiC with Eg = 3.2 eV, wurtzite-GaN with Eg = 3.4 eV) can reduce the energy loss of PE devices by over 50%. b Using ab initio HT simulation, all (a total number of 153,235) materials in the Materials Project are massively screened to search for the best next-generation ultra-wide-bandgap (UWBG) candidates. Here, ns is atom species; na is atom number; a.n. is maximum atomic number; Eg is bandgap; Eh is hull energy; Ec is cohesive energy; μ is electron mobility; к is thermal conductivity. c Retrieve intrinsic properties of materials from the Materials Project (MP) website. d The Baliga figure of merit (FOM), FB, and the Johnson FOM, FJ, are obtained by combining DFT, DFPT, and BTE. Here, C is elastic constant, D is deformation constant, Eg is bandgap, Eb is breakdown field, m* is electron effective mass of; En(k) is electronic dispersion; ωpo is maximum polar optical phonon frequency at Г-point in the Brillouin zone; εs is static dielectric constant; ε∞ is high-frequency dielectric constant; vs is electron saturation velocity; sadp, spop, and simp are differential scattering rates of acoustic deformation potential scattering, polar optical phonon scattering and impurity scattering; μ is electron mobility. e Through the screening process, promising next-generation power semiconductor materials can be identified.
