Scientists at International Business Machines Corp. (IBM, Armonk, NY) claim to have found a way to make thin films of semiconducting materials that allow electrical charges to move through them about 10 times faster than had been reported for all other similar approaches. The research, conducted at IBM's T.J. Watson Research Center, finds that such an increase in charge "mobility" (a measure of how fast electronic circuits made with a semiconductor can operate) can enable a broad array of low-cost electronics and new pervasive-computing applications.
Spin coating has been used before but, until now, has resulted in low charge mobility. IBM is claiming to have developed a way to dissolve such higher-mobility materials in a liquid that could be used in a spin-coating process, leaving a very uniformly controlled film that exhibited 10 times the charge mobility of any previously spin-coated material.
Specifically, scientists combined solvent hydrazine — a molecule made up of two nitrogen and two hydrogen atoms — with equal numbers of chalcogen atoms and semiconducting metal chalcogenide molecules to dissolve the semiconducting material. Heating the resulting film causes both the hydrazine and extra sulfur to dissociate and evaporate, leaving a thin layer of solid metal chalcogenide with a uniform thickness as small as about 5 nm.
