Experimental determination of tunneling characteristics and dwell times from temperature dependence of Al/Al${}_2$O${}_3$/Al junctions

Abstract

Measurements of current-voltage (I-V) characteristics of a high quality Al/Al${}_2$O${}_3$/Al junction at temperatures ranging from 3.5 K to 300 K have been used to extract the barrier properties. Fitting results using Simmons' model led to a constant value of barrier width $s$$\sim$20.8~$\text{A˚}$ and a continuous increase in the barrier height with decreasing temperature. The latter is used to determine the energy band gap temperature dependence and average phonon frequency $\omega$ = 2.05 $\times$ 10${}^{13}$ sec${}^{-1}$ in Al${}_2$O${}_3$, which adds confidence to the precision of our measurements. The barrier parameters are used to extract the temperature dependent dwell times in tunneling (${\tau }_D$ = 3.6 $\times$ 10${}^{-16}$ sec at mid-barrier energies) and locate resonances above the barrier.

arXiv comment3 figures