Scientists have developed a new way to control the electronic properties of materials. They created a pattern of nanoscale holes in a thin layer of a metal oxide known as titania. This markedly increases the flow of electrons and inhibits the flow of ions in the material. Just like ripples in a pond, electrons moving in waves interfere to create unique patterns. This increases titania’s ability to conduct electricity. The researchers used direct imaging of local electric fields to gain insight 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 demonstrates how to use nanoscale patterns to control the electrical properties of titania. Researchers can leverage this control for next-generation applications of microelectronics and quantum information processing. In both of these fields, scientists exploit the exotic behavior of atoms on small scales. The result will be transformative changes in the field of information processing on a practical scale.
Metal oxide thin films have an attractive feature with practical applications, especially in electronics. Titania, for example, displays excellent oxygen vacancies and electron transport properties. Scientists at Argonne National Laboratory, University of Chicago, and Technion − Israel Institute of Technology found a way to exploit these features.
Normally, when an electric current is applied to an oxide such as titania, electrons flow through the material in simple waves. At the same time, ions — or charged particles — are also moving. These processes give rise to the electronic transport properties of materials, such as conductivity and resistance, which are exploited in the next generation of microelectronics designs. The researchers made a thin film of titania and created a pattern of holes 10 to 20 nanometers apart. Through transmission electron microscopy investigations, measurements and modeling of the electrical properties, the researchers demonstrated that the geometric pattern constrains the movement of oxygen and ions in the material and enhances the movement of electrons. As a result, the conductivity of the material increases. This research shows that nanoscale confinement is a way to control quantum interference.
This work is supported by the Department of Energy Science, Office of Basic Energy Science, Materials Science and Engineering Division. This work was carried out in part at the Center for Nanoscale Materials, a user facility of the Department of Energy’s Office of Science.