Development of InSbN alloys for 8 to 12 micron room temperature infrared photodetectors

Indium antimonide (InSb) has the smallest energy gap in the binary III-V materials, with a cut off wavelength of 7 μm at 300 K. The introduction of nitrogen into InSb causes a phenomenon of a strong negative band gap bowing effect, leading to the extended response wavelength of 8 μm to 12 μm range, which provides an alternative for long wavelength infrared photodetection. In this Supplementary Equipment Project for development of InSbN alloys for 8 to 12 micron room temperature infrared photodetectors, we are granted funding for buying some InSb wafers and an Infrared laser. The InSb wafers are used for formation of InSbN alloys by ion implantation of nitrogen and the laser is used for optical characterization. As planned, we have fabricated InSbN alloys by ion implantation under different conditions and characterized them accordingly. In this report, we attempt to show what happen when nitrogen is incorporated to the InSb material. The fabrication, structure, electrical, and band gap properties of InSbN are presented. A thin layer of InSb1-xNx has been fabricated by nitrogen implantation in the near-surface region of the InSb wafers. Hall measurement shows that higher annealing temperature will result in lower carrier concentrations and stronger metallic properties. X-ray photoelectron spectroscopy indicates the formation of oxides including In2O3 and Sb2Ox. When the implanted impurities increase, less percent of them will occupy the anion lattice sites, but the total substitutional nitrogen atoms still steadily increase. Photocurrent measurements prove the bandgap reduction and the existence of negative bandgap. The diffusion behavior of implanted nitrogen in InSb has been ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library 3 studied by SIMS. A strong movement of nitrogen towards the sample surface was observed. The nitrogen concentration peaks are found linearly shifted to the deep region position with the annealing time and temperature. Diffusion coefficients at various temperatures are plotted. The corresponding activation energy for nitrogen in InSb is found to be 0.55eV