Direct measurements of heterobarrier leakage current and modal gain in 2 . 3 pm double OW psubstrate InGaAsSb / AIGaAsSb broad area lasers

Recent success in the design of broadened waveguide lasers [l] has made possible the operation of mid-infrared GaSb-based lasers above room temperature due to a reduction of internal loss. Measurements of temperature dependencies of heterobamer leakage and modal gain are essential for a better understanding of the role of different phenomena determining the device temperature performance. To measure the heterobarrier leakage current of holes in 2.3 p InGaAsSb/AlGaAsSb lasers, we designed and fabricated broad area devices on p-substrates. Essentially, we have grown an n-p-p+ hole collector on the top of a laser structure. The inset in Fig. 1 shows schematically the band diagram of the laser with the collector under bias. The holes emitted from the active region into the n-cladding layer were collected by a small reverse biased pn junction on the top of n-cladding. The saturation current of the collector directly reflects the carrier leakage. This technique was previously applied to Id'-based lasers to measure the leakage of electrons [2]. 201 . . . , . . . I . . . , I . . ,