Unvealing GaN Polytypism in Distributed GaN/InAlN Bragg Reflectors Through HRTEM Image Simulation

Abstract

In this work, through high resolution transmission electron microscopy (HRTEM) and image simulation, the origins of the reduced reflectivity values measured for a nearly lattice‐matched GaN/InAlN distributed Bragg reflector (DBR) are investigated. HRTEM images reveal significant structural defects in the GaN semiperiods, such as coexistence of wurtzite and zinc blende phases and zinc‐blende twinned domains, which contribute to the experimentally observed decrease in reflectivity. Contact regions arising because of the superposition of both cubic and hexagonal GaN polytypes and/or cubic twinned domains are modeled and used to simulate HRTEM images that confirm the experimental phase contrast and hence the validity of the proposed models.

Advanced Hybrid GaN/ZnO Nanoarchitectured Microtubes for Fluorescent Micromotors Driven by UV Light

“…The WZ/ZB polytypism which is often observed in nanoscale III-V semiconductors is attributed to small differences in the energy landscape. Numerous reports exist about GaN thin films grown on various substrates [66][67][68][69] and GaN WZ nanowires [70][71][72][73] in which small ZB domains introduce quantum-well like electronic transition states. Hence, the controlled design of the defect structure, growth orientation, and crystal dimensions of heterostructure NWs for purposive application is investigated thoroughly by studying the growth kinetics [64,65] and the influence of the substrate and metal catalyst.…”