Design and fabrication of infrared detectors based on lattice-matched InAs0.91Sb0.09 on GaSb

The InAs0.91Sb0.09 ternary compound grown on GaSb substrates is a promising alloy for light detection in the 3–View the MathML source window. Nevertheless, its development is still limited due to difficulties occurring during device processing. For example, the use of dry etching for the processing of InAs0.91Sb0.09 p–i–n photovoltaı̈c detectors induces a strong leakage current along the mesa edge. In this letter, we show an improvement of the R0A characteristic by several orders of magnitude at low temperature by using an ion beam etching (IBE) followed by a wet chemical etching. This optimized and reliable device processing allows us to demonstrate that the detector performance is actually limited by the diffusion current of holes. Finally, we discuss the ability of an n-type barrier made of the InAs/AlSb super-lattice to prevent hole diffusion and to improve the R0A characteristic of these detectors.