Experimental observation of the dynamical image potential in extremely low GaAs/Al_xGa_1-xAs/GaAs tunnel barriers

Tunneling in low-barrier GaAs/AlxGa1-xAs/GaAs heterostructures has been systematically investigated over a wide range of barrier heights and thicknesses. Measured conductance data have been compared with tunnel conductances calculated with and without the image potential correction. Experimental evidence is found for the validity of the static image correction in the limit of large tunneling times, and for the occurrence of dynamic effects in the limit of short tunneling times.