nipi delta-doping superlattices for amplitude modulation

GaAs/AlGaAs multiple quantum well structures containing an nipi delta-doping superlattice, where the n-type doping is inserted in the quantum wells and the p-type in the barriers, have been studied in detail to evaluate their potential for use in the fabrication of amplitude modulators. It is shown that C is an adequate p-type dopant for such structures, however, little exibility is found in the growth conditions, in particular for the V to III uxes ratio, for obtaining such layers. It is also observed that the required balance between n and p type doping levels is not trivial to be achieved due to the presence of interface hole traps whose population depends on the quantum well doping concentration. In addition, the observed photoluminescence near-edge emission at room temperature occurs at essentially the same energy as that of an equivalent undoped structure. Finally, no deep level emissions are observed which could deteriorate the device performance.