Nonuniform radiative recombination in n - I - p LED

Radiative recombination of InAs/GaSb superlattice (SL) n - I- p light emitting diodes (LED) was studied theoretically and experimentally. It is shown that recombination takes place not uniformly in the whole SL i region but in a very close vicinity of the p contact. The physics behind this is the formation of high electric field and high carrier concentration domains in a biased device near SL interfaces with the contacts. As a result, in narrow hole miniband the hole vertical diffusion coefficient falling off with the electric field is so small that holes are confined very close to the p contact. This reduces the effective recombination area to 1-2 periods of the SL.