Uniaxial stress dependence of current-voltage characteristics in GaAs-Al_xGa_1-xAs-GaAs heterojunction barriers

Current-voltage characteristics of nGaAs-iAlxGa 1-xAs-nGaAs heterojunction barriers grown on (100) substrates have been measured under uniaxial stress along 〈100〉 at 77 K. The results show that thermionic emission current through longitudinal X valleys becomes dominant over Fowler-Nordheim tunneling current through Γ or transverse X valleys, as stress increases. From the stress-dependent thermionic emission current the rate of change with stress of the band-edge energy difference between Γ in GaAs and longitudinal X in AlGaAs is deduced to be 14±2 meV/kbar, which leads to an X-valley shear deformation potential of 9.6±1.8 eV.