XU Chunlong1*, WANG Zhen1, ZUO Yalu2, XI Li2, SHI Guojie1
(1 Department of Applied Physics, Chang′an University, Xi′an 710064, Shaanxi, China; 2 Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, Gansu, China)
Abstract:
A thermal evaporation method in high vacuum has been developed to synthesize N,N′-Di-\[(1-naphthalenyl)-N,N′-diphenyl\]-1,1′-biphenyl)-4,4′-diamine (NPB) nanodot arrays. The morphology of the sample was investigated with SEM and AFM. A cycle-testing of field emission behavior was carried out for NPB nanoarrays. The field-emission characteristics of the nanodot arrays exhibit that turn-on field is 4.5 V/μm, the threshold field is 15 V/μm and a maximum current density is 1.68 mA/cm2. A obvious hysteresis in the cycle testing with continuous rising and falling current density was observed in the case of the considered samples, which can be attributed to microstructure and adsorption/desorption effect.It is shown that the NPB nanodot arrays showed good current stability in a long time test.
KeyWords:
N,N′-Di-\[(1-naphthalenyl)-N,N′-diphenyl\]-1,1′-biphenyl)-4,4′-diamine (NPB); thermal evaporation; nanodot arrays; field emission
