Room-Temperature Atomic Layer Deposition of Aluminum Silicate and its Application to Na- and K-Ion Sorption

Room-temperature (RT) atomic layer deposition (ALD) of aluminum silicate is developed with a successive adsorption process of tris(dimethylamino)silane (TDMAS) and trimethylaluminum (TMA) using an oxidizer of plasma-excited humidified Ar. The Si-to-Al atomic ratio in the deposited film is controlled by the ratio of TMA and TDMAS exposures. RT deposition of the aluminum silicate film on Si and polyethylene naphthalate films is demonstrated. The ion sorption ability of Na and its exchange with K are demonstrated on the RT-deposited aluminum silicate. The ion sorption of Na in a NaCl solution is maximum when the Si atomic content is balanced with that of Al. The applicability of the RT-deposited aluminum silicate as an ion-sensing surface is discussed.