Humidity Stability of All-Sputtered Metal-Oxide Electric-Double-Layer Transistors

Previous methods of making metal-oxide electric-double-layer transistors (EDLTs) usually require a combination of different vacuum- or solution-based deposition techniques. Recent work has shown that sputtering offers another possibility to prepare oxide proton-conducting dielectrics for metal-oxide EDLTs. In this work, aluminum oxide proton-conducting dielectric is deposited by the dc reactive sputtering method, which helps the fabrication of fully metal-oxide EDLTs only with the sputtering technique. Humidity dependence of the obtained metal-oxide EDLTs is studied. It is found that humidity is a critical factor influencing the electrical characteristics. The underlying mechanism of humidity dependence is analyzed. Encapsulation of the device with polymer is demonstrated to provide basic isolation from humidity variation and stabilize the device.