Fully transparent field-effect transistor with high drain current and on-off ratio
Jisung Park, Hanjong Paik, Kazuki Nomoto, Kiyoung Lee, Bo‐Eun Park, Benjamin Grisafe, Lichen Wang, Sayeef Salahuddin, Suman Datta, Yongsung Kim, Debdeep Jena, Huili Grace Xing, Darrell G. Schlom
Abstract
We report a fully transparent thin-film transistor utilizing a La-doped BaSnO3 channel layer that provides a drain current of 0.468 mA/μm and an on-off ratio of 1.5 × 108. The La-doped BaSnO3 channel is grown on a 100–150 nm thick unintentionally doped BaSnO3 buffer layer on a (001) MgO substrate by molecular-beam epitaxy. Unpatterned channel layers show mobilities of 127–184 cm2 V−1 s−1 at carrier concentrations in the low to mid 1019 cm−3 range. The BaSnO3 is patterned by reactive ion etching under conditions preserving the high mobility and conductivity. Using this patterning method, a sub-micron-scale thin film transistor exhibiting complete depletion at room temperature is achieved.