InNxSb1−x Light Emitting Diodes Grown by MBE

Abstract

We present the first reported MBE growth of light emitting diodes (LED's) with active regions made up of InSb/ InNxSbl−x (O<x<0.02) superlattices, grown onto InSb(100) substrates. Such dilute alloys of nitrogen in other III-V materials have been shown to exhibit very large bandgap bowing parameters due to differences in atomic size and the electro-negativity of nitrogen. Novel growth techniques have been developed to enable epitaxy of high quality InNxSbl−x, using an electron cyclotron resonance (ECR) plasma source. Material characterisation was performed by double crystal x-ray diffraction (DXRD) and transmission electron microscopy (TEM), and nitrogen composition has been determined using DXRD and secondary ion mass spectrometry (SIMS). To determine the effect of nitrogen on bandgap, the structures have been fabricated into LED's with InSb/InNxSbl−x superlattice active regions with period ∼1100A. For a nitrogen content of ∼0.3%, the peak emission of the diodes shifts from ∼6pm to >71µm at room temperature.