Strong Band-Edge Light Emission from InGaAs RTDs: Evidence for the Universal Nature of Resonant- and Zener- Co-Tunneling

We report strong light emission from a room-temperature n-type unipolar-doped In0.53Ga0.47As/AlAs double-barrier resonant-tunneling diode (DBRTD) precisely at the In0.53Ga0.47As band-edge near 1650 nm. The emission characteristics are very similar to what was observed recently in GaN/AlN DBRTDs, both of which suggest that the mechanism for emission is cross-gap electron-hole recombination via resonant- and Zener co-tunneling of electrons, the latter mechanism generating the required holes. Analysis shows that because of the relatively small bandgap, the Zener tunneling probability can be large in this In0.53Ga0.47As/AlAs DBRTD, and is a mechanism that may have been overlooked in the longstanding literature. The universal nature of the co-tunneling is best supported by the factor (EG)2/F in the Kane tunneling probability, which is nearly the same at the peak voltage of the In0.53Ga0.47As and GaN DBRTDs.