Electron tunneling in GaAs/AlGaAs heterostructures

Electron transport through thin (100) GaAs / AlGaAs / GaAs tunnel junctions is analyzed within an empirical pseudopotential formulation. The current transmission coefficient is calculated for a variety of junction widths between 1 and 8 monolayers. Alloy concentrations of x = 0.25 and x = 1 are considered. The results for the wider AlAs junctions show significant deviations from the values predicted by effective mass theory. This is shown to be due to electron transport primarily occurring via the X
₁
state of the AlAs.