Oxide thin films are widely used in many devices, such as memristors, dye sensitized solar cells, chemical sensors, micro-batteries and micro-fuel cells. One attractive feature of oxide thin films is that their properties can be tuned to cover a wide range of limits, with high precision, by varying the oxygen content. As a result, a technique that enables precise control of the oxygen content of films in situ, is highly desirable.
To address this problem, a MIT research group led by Professor Harry L. Tuller has conducted a series of experiments to attempt to control the oxygen content of oxide thin films in situ through electrochemical methods. Their research has successfully demonstrated that the oxygen content can be manipulated in a fast, precise and convenient manner by varying the bias across an electrochemical cell. The initial challenge lies with the delicacy of using a film with only 100 nanometers thickness (1/600 of the diameter of a human hair). Nevertheless, their experiments have reached an effective oxygen partial pressure that is as high as 280 atmospheric pressure, which is unprecedented and extremely difficult to achieve through existing methods.
“This technique will open up a wide range of opportunities in both academic research and industrial applications”, says Dr. Di Chen, a postdoc at MIT and the lead of this study, “Our next step is to use this technique to study other material properties, such as thermal conductivity or magnetic properties”.