Electron Spin Transport Facilitated by a Low Work Function Metal in Alq3

Since the first experimental observation on spin transport in tris-(8-hydroxyquinoline) aluminum (Alq3) was reported,[3] the focus has been on holes as the spin carrier because the work functions of ferromagnetic materials are close to the highest occupied molecular orbital (HOMO) of Alq3 even though electron transport is preferred in Alq3.[4,5] Therefore, the experimental observation of spin polarized electron transport in Alq3 requires the modification of band alignment between Alq3 and metal electrodes.[6] In this report, we present our experimental demonstration of spin polarized electron transport over a distance of 150 nm in Alq3 by using a thin layer of Ca insert and thus facilitating the injection of spin polarized electrons into and extraction from Alq3.