Atomic-Scale Insights into the Interfacial Polarization Effect in the InGaN/GaN Heterostructure for Solar Cells

The model system of the InGaN/GaN quantum wells (QWs), based on the first principles calculation, was chosen to understand the underlying mechanism of interfacial polarization and its synergic effect with the built-in electric field (B_ef) at the p-n junction in solar cells (SLs). The polarized electric field (P_ef) was generated due to the redistribution of electrons and holes at the interface; moreover, the P_ef of InGaN/GaN heterostructure on the semipolar (01-11) GaN surface was consistent with that of on the N-polar (000-1) surface, which is on the lines of the B_ef and favors the electron-hole separation efficiency in SLs. Furthermore, the growth of high-quality InGaN/GaN QWs on the semipolar (01-11) GaN surface was achieved. Such an atomic-scale investigation provides a fundamental understanding of the polarization charge-induced P_ef and its interaction coupling with B_ef at the p-n junction, which could be generalized to polar material-based SLs.