Evidence of Type-II Band Alignment in III-nitride Semiconductors: Experimental and theoretical investigation for In_0.17Al_0.83N/GaN heterostructures

摘要

Type-II band alignment structure is coveted in the design of photovoltaic devices and detectors, since it is beneficial for the transport of photogenerated carriers. Regrettably, for group-III-nitride wide bandgap semiconductors, all existing devices are limited to type-I heterostructures, owing to the unavailable of type-II ones. This seriously restricts the designing flexibility for optoelectronic devices and consequently the relevant performance of this material system. Here we show a brandnew type-II band alignment of the lattice-matched In_0.17Al_0.83N/GaN heterostructure from the perspective of both experimental observations and first-principle theoretical calculations. The band discontinuity is dominated by the conduction band offset Δ E_C , with a small contribution from the valence band offset Δ E_V which equals 0.1?eV (with being above ). Our work may open up new prospects to realize high-performance III-Nitrides optoelectronic devices based on type-II energy band engineering.