Based on the classical Varshni model, the empirical relationship Eg (x, T) of the energy band value Eg of In1-xAlxSb with Al composition and temperature is proposed, and the validity of the formula is verified by the existing literature data. Experimentally, an InAlSb epitaxial layer with p +-p+ -n-n+ barrier structure is grown on InSb (100) substrate by molecular beam epitaxy. The crystal quality and Al composition of the material are tested and characterized by high-resolution X-ray diffraction, and the Al composition is calculated to be 2.8%. Then, the InAlSb material is prepared as an infrared detector diode and the spectral response curve under 77~260 K is measured, thereby the relationship between the energy band value of the In0.972Al0.028Sb material and the temperature can be calculated. The data are basically consistent with the theoretical derivation. The determination of the relationship between InAlSb energy band value, Al composition and temperature can provide necessary theoretical support for the design of the detector material structure.
