SHALLOW STRAINED INXGA1-XAS INYGA1-YAS SUPERLATTICES EMBEDDED IN P-I-N-DIODES - STRUCTURAL-PROPERTIES AND OPTICAL-RESPONSE/

In1-xGaxAs/In1-yGayAs strained layer superlattices grown on InP substr ates are interesting candidates for optoelectronic device applications . When embedded in the intrinsic region of a p-i-n diode, the optical properties of such shallow strained superlattice devices depend critic ally on the precise control of the layer parameters and the built-in e lectric field. In this work, we investigate in detail the structural a nd optical properties of a series of In1-xGaxAs/In1-yGayAs superlattic es with nominally lattice-matched wells and up to 1.5% tensile straine d barriers, embedded in the intrinsic region of InP p-i-n diodes. The structural parameters have been determined from a careful line-shape a nalysis of x-ray rocking curves. An accurate model of the field-depend ent electronic states in the superlattices has been developed. We find that the analysis of absorption and emission experiments requires tak ing into account the electric field screening by the photoinduced carr iers. For fields above a few kV/cm, the optical properties are dominat ed by the mixed type-I-type-II band structure of the strained superlat tices.