Modifying spin injection characteristics in the Co/Alq3 system by using a molecular self-assembled monolayer
Hyuk-Jae Jang, Jun-Sik Lee, Sujitra J. Pookpanratana, Ich C. Tran, Curt A. Richter, Christina A. Hacker
We present the results of experiments that explore the influence of molecular self-assembled monolayers (SAMs) on characteristics of spin injection into an organic semiconductor, Alq3 [tris-(8-hydroxyquinoline) aluminum] from a ferromagnetic metal, Co. Two different SAMs, MHA (16-mercaptohexadeconic acid; HS(CH2)15CO2H) and ODT (1-Octadecanethiol; CH3(CH2)17SH) are inserted between Alq3 and Co layers and their effects on electronic structure hybridization and related changes in energy levels and spin dependent properties at the interface are investigated. X-ray photoelectron measurements of the surface structure for the MHA, ODT, and Alq3 organic layers provide bonding and chemical conformational information. Ultraviolet photoelectron spectroscopy (UPS) measurements reveal that both MHA and ODT treatments lower the work function of Co. X-ray magnetic circular dichroism (XMCD) spectra imply that SAMs reduce the hybridization between Co and Alq3 and furthermore, they enhance the spin magnetic moment of Co.
, Lee, J.
, Pookpanratana, S.
, Tran, I.
, Richter, C.
and Hacker, C.
Modifying spin injection characteristics in the Co/Alq3 system by using a molecular self-assembled monolayer, Journal of Physical Chemistry C, [online], https://doi.org/10.1021/acs.jpcc.5b01222
(Accessed September 21, 2021)