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An Indium Arsenide Bismide photodiode has been grown, fabricated, and characterized to evaluate its performance in the Mid Wave Infrared region of the spectrum. Spectral response from the diode has been obtained up to a diode temperature of 225 K. At this temperature, the diode has a cut off wavelength of 3.95 lm, compared to 3.41 lm in a reference Indium Arsenide diode, indicating that Bismuth has been incorporated to reduce the band gap of Indium Arsenide by 75 meV. Similar band gap reduction was deduced from the cut off wavelength comparison at 77 K. From the dark current data, shunt resistance values of 8 and 39 X at temperatures of 77 and 290 K, respectively, were obtained in our photodiode. V

This work analyses the Bi incorporation in InAs1-xBix/InAs(100) epilayers grown by MBE through advanced transmission electron microscopy techniques. Samples grown from 350–400 °C resulted in Bi contents <3.3% exhibiting compositional variation in the growth direction. In contrast, roughly spherical clusters appeared in the sample grown at lower temperatures. The clusters are made up of the binary InBi with a tetragonal PbO phase surrounded by a matrix of InAs0.95Bi0.05 indicating the Bi solubility limit in InAs. These InBi crystals underwent a cubic distortion and are tilted 55° with regard to the InAsBi matrix. The crystallographic relationships are analysed in detail.

The absorption properties of GaAsBi have been investigated using GaAsBi based p-i-n diodes with different bismuth compositions (∼2.1 and ∼3.4%). The absorption behaviour of GaAsBi as a function of incident photon energy above the band gap follows that of a direct band gap material. With increasing bismuth content, the absorption of photons with energy lower than the band gap in GaAsBi is enhanced, probably due to localized states caused by Bi-related defects. A simplified analysis has been undertaken on the behaviour of absorption as a function of bias voltage. By undertaking photoresponsivity measurements as a function of reverse bias, the background doping type and the minority carriers diffusion lengths in GaAsBi have been determined.