OXIDE THIN FILMS REPLACING PN JUNCTIONS.
North Carolina State University have developed the first functional oxide thin films that can be used efficiently in electronics, opening the door to an array of new high-power devices and smart sensors. This is the first time that researchers have been able to produce positively charged (p-type) conduction and negatively charged (n-type) conduction in a single oxide material, launching a new era in oxide electronics.
To make functional electronic devices, you need materials with a “p-n junction,” where the positively charged and negatively charged materials meet. Solid state silicon electronics achieved this decades ago, but are limited by the amount of power and temperature they can handle. Oxide materials are an attractive alternative to silicon because they can handle more power.
However, attempts to pair different p-type and n-type oxide materials previously ran into problems at the interface of the two materials — the p-n junction was always inefficient.
Specifically, Narayan’s team used lasers to create positively charged nickel oxide (NiO) thin films, then converted the top layer of those films to n-type. Because they could control the thickness of the n-layer, the researchers were able to control the depth and characteristics of the p-n junction.
By enabling the development of oxide electronics, the research allows for the creation of a host of new technologies in a wide array of fields. For example, because oxides can handle higher voltages than silicon-based electronics, the material could be used to create higher voltage switches for the power grid, which would allow more power to be transmitted on the existing infrastructure. Similarly, this would allow the development of sensors for use in higher-temperature environments, because oxides are more stable at high temperatures.
Oxide electronics could also be used to create new sensors for monitoring gases, since oxide materials can interact with oxygen. These sensors could have a variety of applications, including testing for air toxicity in security situations.They also are transparent.