ELECTRON-WAVE INTERFERENCE EFFECTS IN A GA1-XALXAS SINGLE-BARRIER STRUCTURE MEASURED BY BALLISTIC-ELECTRON-EMISSION SPECTROSCOPY

Ballistic electron emission spectroscopy (BEES) has been performed on a GaAs/Ga0.8Al0.2As/GaAs single-barrier structure at 77 and 7 K. The s ingle-interface model widely used for such structures was found to be inadequate in describing the BEES second-derivative spectrum. A more c omplete model that incorporates electron-wave interference effects is shown to describe the data accurately and consistently over many spati al locations and samples, This model reproduces all measured features in the BEES second-derivative spectrum resulting from electron-wave in terference. At 77 K (7 K) the conduction band offset for x=0.2 is dete rmined to be 145 meV or Q(c)=0.58 (150 meV or Q(c)=0.60) in agreement with accepted values. (C) 1997 American Institute of Physics.