Field emission enhancement of ZnO nanorod arrays with hafnium nitride coating

• Published in: Surface & coatings technology 2008-04, Vol.202 (15), p.3480-3484
• Main Authors: Yuan, Longyan, Fang, Guojia, Li, Chun, Li, Jun, Wang, Mingjun, Liu, Nishuang, Zhao, Xingzhong
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Field emission; Hafnium nitride coating; Materials science; Metals. Metallurgy; Physics; Production techniques; Surface treatment; Surface treatments; ZnO nanorod arrays
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2007.12.023

Vertically well-aligned single crystal ZnO nanorod arrays were synthesized and enhanced field electron emission was achieved with hafnium nitride (HfN x ) coating under proper sputtering condition. HfN x films with various composition have been coated on ZnO nanorod arrays using a reactive direct current (DC) magnetron sputtering system. Morphology and crystal configuration of the ZnO nanorod arrays were investigated by scanning electron microscopy and X-ray diffraction. The field emission properties of the coated and uncoated ZnO nanorod arrays were characterized. The as-grown ZnO nanorod arrays showed a turn-on electric field of 6.60 V μm − 1 at a current density of 10 μA cm − 2 and an emission current density of 1 mA cm − 2 under the field of 9.32 V μm − 1 . While the turn-on electric field of the coated ZnO nanorod arrays sharply decreased to 2.42 V μm − 1 , an emission current density of 1 mA cm − 2 under the field of only 4.30 V μm − 1 can be obtained. A method to accurately measure the work function of the coated films was demonstrated.