Resonant tunneling in InGaAs-InP double-barrier structures and superlattices

In the last few years, there was a great deal of renewed interest in the vertical, tunneling transport in double-barrier tunneling structures (DBTS), which were shown to be possible microwave oscillators. To date, most of the work on DBTS was performed using GaAs-AlGaAs structures because of the excellent control in both the growth and the device processing of this system. The first study of DBTS of the In(0.53)Ga(0.47)As-InP system, which is an important one in optoelectronics, is presented. The first devices fabricated using the usual mesa-etching procedure showed a large non-tunneling current which was ascribed to surface leakage current at the sides of the mesas, since this was often a problem with similar devices of this system. By additional mesa-etching which selectively etch the InGaAs layer faster than the InP layer, the surface leakage current was greatly reduced, and the characteristic current peaks associated with resonant tunneling become well developed. The voltage values at the resonances are in fair agreement with the theoretical predictions. The transport properties of the InGaAs-InP DBTS show interesting differences with those of the GaAs-AlGaAs system, of which the most remarkable is the symmetry about zero bias voltage in the former device. These results will be discussed with preliminary results related to the vertical transport in superlattices of the InGaAs-InP system.