Numerical analysis of longwavelength extracted photodiodes

The electrical and photoelectrical properties of the longwavelength n⁺πp⁺ Hg_1−xCd_xTe structures have been analyzed numerically. The band diagram, electrical field, photoelectrical gain, responsivity, noise and detectivity have been calculated as a function of voltage applied. The calculations have been performed for devices prepared from Hg_1−xCd_xTe, optimized for optimum performance at λ = 10.6 μm, and operated at a temperature of 230 K. Reverse bias results in suppression of Auger generation current in the lightly doped region of the junction. The main contribution to the total noise current comes mostly from the heavily doped p⁺ region and then from regions close to l-h junctions.