Structural changes on the nano-meter scale of thin Ag films on Si(1 1 1) surfaces by NO exposure

The low-temperature (180 K) interaction of NO molecules with thin Ag films deposited on hydrogen terminated Si(1 1 1) is investigated by X-ray photoelectron spectroscopy, scanning electron microscopy and chemicurrent measurements. The chemicurrent transients recorded from the thin film Ag/Si Schottky diodes demonstrate two maxima according to NO molecular adsorption and intermolecular reactions of (NO)2 dimer decomposition. Below a critical film thickness of 8 nm the original smooth Ag films are disrupted by the NO exposure leading to a nano-patterned network of coalescing Ag islands. Thicker films are stable upon NO exposure. Warming of NO-exposed diodes to room temperature changes the Ag/Si interface properties drastically by reducing the effective Schottky barrier height and increasing the diode’s sensitivity to detect electrons excited in the metal. This is observed by enhanced maximum chemicurrents after annealing.