Scientists have developed a new way to control the electronic properties of materials. They created a nanoscale pattern of holes on a thin film of metal oxide known as titania. This noticeably improved the flow of electrons and inhibited the flow of ions in the material.
Like ripples in a pond, the electrons traveling in waves interfered to create a unique pattern. This increased the ability of titania to conduct electricity. The researchers used direct imaging of the local electric fields to gain insights into this phenomenon.
Thin oxide films are found everywhere in modern technology. They appear in computers, cell phones, LEDs, and other electronic devices. This research demonstrated how to use nanoscale patterning to control the electrical properties of titania. Researchers can harness this control for the next generation of microelectronics applications and quantum information processing. In both these areas, scientists are taking advantage of the exotic behavior of atoms at a small scale. The outcome will be transformative changes in information processing on a practical scale.
Metal oxide thin films have attractive features with practical applications, especially in electronics. Titania, for example, displays excellent oxygen vacancy and electron transport properties. Scientists at Argonne National Laboratory, the University of Chicago, and Technion − Israel Institute of Technology discovered a means of exploiting these features.
Usually, when an electric current is applied to an oxide like titania, electrons flow through the material in a simple wave. At the same time, ions — or charged particles — also move around. These processes give rise to the material’s electronic transport properties, such as conductivity and resistance, which are exploited in the design of next-generation microelectronics. Researchers fabricated thin titania films and patterned them with holes 10 to 20 nanometers apart. Through the investigations by transmission electron microscopy, electrical property measurements and modeling, the researchers demonstrated that the geometric pattern restricted the motion of oxygen and ions in the material and increased the electron motion. As a result, the conductivity of the material increased. This research shows that nanoscale confinement is a way to control quantum interference.
This work was supported by the Department of Energy Office of Science, Office of Basic Energy Science, Materials Sciences and Engineering Division. This work was performed in part at the Center for Nanoscale Materials, a Department of Energy Office of Science user facility.