Non-Ideal Quantum well Structures

Txhe optical gain and quality of the light emitted in a quantum well structure are analysed in the presence of (a) optical, electrical and thermal couplings between adjacent wells, (b) tunnel leakage, (c) non-radiative and radiative interface recombinations, (d) lattice mismatch, (e) inhomogenity of the layers, (f) ratio of the width of the well to that of the barrier and (g) number of wells. It is felt that the thermalisation of the carriers through collisions with phonons is not necessarily an advantageous feature. Instead several alternatives like (i) mixed electrical and optical pumping mode techniques, (ii) creation of some metastable levels in the wells, (iii) longitudinal magnetic focussing or transverse magnetic deflection and (iv) several other junction pairs starting from GaAs/AlGaAs are discussed for illustrative purposes. Upconversion and mixing frequency techniques can be developed by impregnating barrier/well materials with slight additions of luminiphors as impurities. © 1987 SPIE.