INAS/ANTIMONIDE-BASED RESONANT-TUNNELING STRUCTURES WITH TERNARY ALLOY LAYERS

We have studied two modifications of mixed arsenide/antimonide resonant tunneling structures, in which one of the binary components is replaced by a ternary alloy. The first structure is based on an InAs/AlSb/GaSb resonant interband tunneling structure with the GaSb quantum well layer replaced by a GaAsxSb1-x alloy layer. The added As decreases the lattice constant in the well, and the resulting strain can shift the heavy hole subbands below the incoming electron energy. We find that the negative resistance effect can be enhanced by properly adjusting the splitting via the As concentration. A maximum enhancement in the peak-to-valley ratio was obtained with a 10% As concentration in the diodes we fabricated. The second structure is a modification of a conventional InAs/AlSb double barrier structure, in which the AlSb barriers are replaced by AlxGa1-xSb with x almost-equal-to 0.5. In these structures, the pronounced type II band alignment results in an entirely new type of current vs voltage characteristic exhibiting intrinsic current bistability (double-valued currents for a given voltage) instead of the conventional voltage bistability. Peak-to-valley voltage ratios as high as 1.5 have been observed with current densities in the 10(5) A/cm2 range.