Uniaxial stress dependence of the current-voltage characteristics of n-type AlAs/GaAs/AlAs tunnel diodes at 77 K

Longitudinal uniaxial stress along 〈100〉 has been applied in AlAs-GaAs-AlAs resonant tunneling heterostructures grown on (100) substrates to study the current-voltage characteristics as a function of stress. We find that the nonresonant current is due to Fowler–Nordheim tunneling currents by both longitudinal and transverse X valleys (X1 and Xt). This current decreases with low stress (<1 kbar), increases with intermediate stress and decreases with high stress (>9 kbar) again. This is due to the increase of the Xt barrier at low stress, the decrease of the X1 barrier at intermediate stress, and the formation and the increase of X1 potential well depth at high stress. We also find a large unexplained monotonic decrease of the resonant current through the Γ valley.