High room temperature mobility in Al2O3/SrTiO3 heterostructures

Abstract Al 2 O 3 /SrTiO 3 heterostructures have attracted wide attention because of high electron mobility at cryogenic temperatures. But very low room temperature mobility (typically less than 12 cm 2 V −1 s −1 ) limits its potential application. Here, the Al 2 O 3 /SrTiO 3 heterostructures are successfully prepared by the low-cost magnetron sputtering. We observed that room temperature mobility is gradually enhanced on increasing electron concentration, and a maximum of 41.1 cm 2 V −1 s −1 is obtained. This can be attributed to the high electron concentration due to the longitudinal optical phonon scattering. Our findings not only offer a route to improve room temperature mobility of the SrTiO 3 -based heterostructures but also provide a new experimental method for fabricating Al 2 O 3 /SrTiO 3 heterostructures.