Researchers at North Carolina State University have developed the first functional Nickel-oxide thin films behaving like the popular semiconductor material; silicon basd PN junction diode.
Dr. Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and his research 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.
Narayan says: this spatial and temporal selectivity provides unprecedented control to 'write' p-n junctions by laser beams and create ultra high-density device features for oxide electronics.
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.
"We avoided this problem by using the same material for p- and n-type conduction," says Narayan "This is a new era in oxide electronics."
Well the material researchers are attempting to convert any material into controlled conductor or insulator of electricity.
The advantage of oxide based semiconductor are they can handle higher voltages than silicon-based semiconductors. Since oxides are more stable at high temperatures they can be more reliable than silicon in high temperature.
Oxide electronics can be also used as gas sensors because they react with gases such as oxygen resulting in new applications.
"These materials are also transparent," Narayan says, "so this makes transparent electronics possible."
The paper, "Controlled p-type to n-type conductivity transformation in NiO thin films by ultraviolet-laser irradiation," is published online in the Journal of Applied Physics. The paper was co-authored by Pranav Gupta, a Ph.D. student at NC State; Narayan; and Drs. Titas Dutta and Siddhartha Mal, both former Ph.D. students at NC State now working at Intel. All India-n names! The research was funded by the National Science Foundation.