Charge injection, transport and localization in rubrene

▶ Ohmic contacts and Schottky contacts with rubrene crystals are studied. ▶ Nonlinear fits of I:V characteristics with Ni80Fe20 contacts give a barrier height of 0.22(1) eV. ▶ Negative magnetoresistance of 4% is observed in 5 T at 70 K for ohmic Ni80Fe20 contacts. ▶ Magnetoresistance is attributed to weak localization, not a spin valve effect. ▶ Spin diffusion length is less than 200 nm.O