Probe pressure effect on tunneling current through a GaAs-(Al,Ga)As-GaAs heterojunction barrier

We have observed a remarkable increase of current through GaAs/(Al,Ga)As/GaAs barrier structures on the application of probe pressure. The increase in current is by many orders of magnitude, and is reversible on removal of the pressure. A rough calculation based on the probe geometry gives a local pressure of tens of kbar over an area of several square micrometers. The phenomenon may be understood in terms of the pressure dependence of the band edges of GaAs and AlGaAs.