Demonstration of Fowler-Nordheim Tunneling in Simple Solution-Processed Thin Films

The production of high-quality thin-film insulators is essential to develop advanced technologies based on electron tunneling. Current insulator deposition methods, however, suffer from a variety of limitations, including constrained substrate sizes, limited materials options, and complexity of patterning. Here, we report the deposition of large-area Al₂O₃ films by a solution process and its integration in metal-insulator-metal devices that exhibit I- V signatures of Fowler-Nordheim electron tunneling. A unique, high-purity precursor based on an aqueous solution of the nanocluster flat-Al₁₃ transforms to thin Al₂O₃ insulators free of the electron traps and emission states that commonly inhibit tunneling in other films. Tunneling is further confirmed by the temperature independence of device current.