Fabrication and characterization of two‐dimensional cubic AlN photonic crystal membranes containing zincblende GaN quantum dots

Abstract

AbstractWe successfully developed a process to fabricate freestanding cubic aluminium nitride (c‐AlN) membranes containing cubic gallium nitride (c‐GaN) quantum dots (QDs). The samples were grown by plasma assisted molecular beam epitaxy (MBE). To realize the photonic crystal (PhC) membrane we have chosen a triangular array of holes. The array was fabricated by electron beam lithography and several steps of reactive ion etching (RIE) with the help of a hard mask and an undercut of the active layer. The r/a‐ ratio of 0.35 was deter‐ mined by numerical simulations to obtain a preferably wide photonic band gap. Micro‐photoluminescence (µ‐PL) measurements of the photonic crystals, in particular of a H1 and a L3 cavity, and the emission of the QD ensemble were performed to characterize the samples. The PhCs show high quality factors of 4400 for the H1 cavity and about 5000/3000 for two different modes of the L3 cavity, respectively. The energy of the fundamental modes is in good agreement to the numerical simulations. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)