Resonant tunneling in Si/Si1−<i>x</i>Ge<i>x</i> double-barrier structures

Abstract

Resonant tunneling of holes has been observed for the first time in double-barrier diodes with strained Si1−xGex quantum wells formed between unstrained Si barriers. Negative differential resistance with a peak-to-valley ratio in current of 1.8 at 77 K and of 2.2 at 4.2 K has been exhibited by a sample with a 3.3-nm-wide Si0.79Ge0.21 well between 6.0 nm Si barriers. The positions of the current peaks are in reasonable agreement with calculations of the positions of heavy-hole levels in the quantum well.