The effect of disorder on electron tunneling in a metal-insulator-metal junction is investigated using the Lloyd model. It is found that weak disorder increases the tunneling current due to a finite density of states near the center of the insulator band gap, while strong disorder decreases the current. The possibility of a negative-resistance region such as was previously found for an ordered insulator persists in the presence of disorder.

• Received 23 May 1977

DOI:https://doi.org/10.1103/PhysRevB.16.2346