Low p-type conductivity and high contact resistance remain a critical problem in wide band gap AlGaN-based ultraviolet light emitters due to the high acceptor ionization energy. In this work, interband tunneling is demonstrated for non-equilibrium injection of holes through the use of ultrathin polarization-engineered layers that enhance tunneling probability by several orders of magnitude over a PN homojunction. Al0.3Ga0.7N interband tunnel junctions with a low resistance of 5.6 x 10(-4) Omega cm(2) were obtained and integrated on ultraviolet light emitting diodes. Tunnel injection of holes was used to realize GaN-free ultraviolet light emitters with bottom and top n-type Al0.3Ga0.7N contacts. At an emission wavelength of 327 nm, stable output power of 6 W/cm(2) at a current density of 120 A/cm(2) with a forward voltage of 5.9 V was achieved. This demonstration of efficient interband tunneling could enable device designs for higher efficiency ultraviolet emitters. (C) 2015 AIP Publishing LLC.