Plasmon-Assisted Directional Infrared Photoluminescence of HgTe Nanocrystals

Abstract

HgTe nanocrystals offer a unique spectral tunability with both absorption and emission covering the near and mid-infrared as well as the THz window. Nevertheless, a very limited amount of work is dedicated to electroluminescence from this material. An efficient diode not only requires designing a structure that achieves a high electrical efficiency (i.e., efficient electron and hole injections), but also finding a way to efficiently extract the emitted photons. The shift from visible to infrared certainly demands revisiting the strategies proposed for shorter wavelengths (microlens arrays). Here, a metallic grating is used to enhance the photoluminscence signal up to a factor of 4 while enabling directionality in the emission, which is driven by the grating period.