Semiconductors and applications

Conventional semiconductors like Si and GaAs are the materials of focus for electronic industry due to its unmatched performance, technological maturity and well-established fabrication methods. However, these materials are found wanting, in a new set of applications that require attributes such as transparency and flexibility. Ultra-flexible and transparent electronics could transform the way we make and use electronic devices. Organic conjugated materials as well as conventional semiconductors embedded in elastomeric substrates have been studied for this purpose with mixed success. The organic conjugated materials have much poorer charge transport properties, while the high growth temperatures of the crystalline inorganic semiconductors require cumbersome transfer processing steps. Herein, we propose to explore an alternate class of semiconductors- Amorphous Metal Oxide Semiconductors (AOS), which have the intrinsic advantages of transparency, good electrical properties, an increased tolerance to strain and low temperature processing. Their amorphous structure enables the realization of uniform device properties over large areas. The charge transport properties of these materials are excellent, with charge carrier mobilities far exceeding that of amorphous silicon (a:Si) and organic materials. However, high performance AOS have not been utilized in flexible, stretchable, conformable e-skin applications. Challenges to be addressed include reduction of the chemical transformation temperature as well as unexplored mechanical properties. The insights drawn about the device and materials design for strain tolerance would be widely applicable for future applications which employ this material set.