Optical properties of strained asymmetric triangular InGaAs/GaAs multiple quantum wells

We present the first report of a strained-layer asymmetric triangular In0.15Ga0.85As/GaAs multiple quantum well structure realized by molecular beam epitaxy. Low-temperature photoluminescence experiments showed that the optical efficiency of such a structure is more than five times higher than an equivalent rectangular In0.15Ga0.85As/GaAs multiple quantum well structure grown under the same conditions. This is due to an increased collection of photoexcited carriers that are being swept by the well as a result of the field formed by compositional grading and a reduction of nonradiative recombination centers.