Low Al-composition p-GaN/Mg-doped Al(0.25)Ga(0.75)N/n(+)-GaN polarization-induced backward tunneling junction grown by metal-organic chemical vapor deposition on sapphire substrate

Low Al-composition p-GaN/Mg-doped Al(0.25)Ga(0.75)N/n(+)-GaN polarization-induced backward tunneling junction (PIBTJ) was grown by metal-organic chemical vapor deposition on sapphire substrate. A self-consistent solution of Poisson-Schrödinger equations combined with polarization-induced theory was used to model PIBTJ structure, energy band diagrams and free carrier concentrations distribution. The PIBTJ displays reliable and reproducible backward tunneling with a current density of 3 A/cm(2) at the reverse bias of −1 V. The absence of negative differential resistance behavior of PIBTJ at forward bias can mainly be attributed to the hole compensation centers, including C, H and O impurities, accumulated at the p-GaN/Mg-doped AlGaN heterointerface.