Single GaN-Based Nanowires for Photodetection and Sensing Applications

Abstract

We present a study of the structural properties of GaN/AlN heterostructured nanowires grown by plasma-assisted molecular-beam epitaxy. We combine transmission electron microscopy measurements with theoretical calculations of the strain distribution and band diagram in order to gain understanding of the potential distribution in these nanostructures. The effects of surface states and of the formation of a core–shell heterostructure are discussed. The structural properties are correlated with the performance of GaN-based nanowire photodetectors and sensors. In particular, we discuss a sensor design where the insertion of an AlN barrier in a GaN nanowire is proposed as a material engineering solution to inhibit the electron transport through the core, confining the current close to the nanowire sidewalls.