Semiconductor Materials - 01

Abstract

Organic radicals have emerged as strong candidates for use in molecular spintronics due to their stable unpaired electrons, chemical tunability, low spin-orbit coupling, and long spin relaxation time.[1-3] In this study, we demonstrate magnetic-field-dependent carrier transport via molecular orbitals of an organic radical, namely {4-[{[2,5-bis(4-sulfanylphenyl[eth-1-yn-2-yl])phenyl]carbonyl} (methyl)amino]-2,2,6,6-tetramethylpiperidin-1-yl}oxidanyl (TEMPO-OPE). The TEMPO-OPE molecules were incorporated as quantum dots in a metal-oxide-semiconductor (MOS) structure. The MOS structure serves as a double-tunnel-junction. A significant reduction in the tunneling current via the HOMO level of the molecules was observed with increasing magnetic field. The large positive magnetoresistance of up to 400 % was detected under a magnetic field of 7 T at a temperature of 3 K. Our findings thus hold great potential for integrating the magnetic functionalities of organic radicals into Si-based devices with complementary metal-oxide-semiconductor (CMOS) compatibility.