Abstract: Magnetoresistance measurement of indium tin oxide/N, N'-Bis(naphthalen-2-yl)-N,N'-bis(phenyl)-benzidine(NPB)/ Tris(8-hydroxy-quinolinato) aluminum(Alq₃)/3-(4-Biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole(TAZ)/LiF/aluminum OLED structures have been made as a function of magnetic field at room temperature. The MR is defined as MR=Δρ/ρ=[ρ(B)-ρ(0)] /ρ(0). It has been found that that the Δρ/ρ increases with increasing magnetic field strength from 0 mT to 110 mT with TAZ thickness of 0 nm at 10 V, which maximal value is 8.22% at about 110 mT. The external magnetic filed can decrease the Δρ/ρ in devices with TAZ thickness from 5 nm to 15 nm. This is because the magnetic field can reduce the singlet polaron pairs converted into triplet polaron pairs due to Zeeman splitting and can lead to an increase in singlet polarons and a decrease in triplet polarons. Furthermore, the Δρ/ρ increases while TAZ thickness is increasing at same magnetic filed strength. When an external magnetic field is 110 mT, the Δρ/ρ is found to increase by up to -16.92% with TAZ thickness of 15 nm at 10 V.

Key words: semiconductor technology, resistance change rate, current change rate, resistance magnetic sensitized effect