Field emission characteristics of AIN coated silicon nanocone arrays

摘要

Nanoscaled silicon cone arrays were formed on mirror-polished silicon wafers by plasma etching using hot filament chemical vapor deposition (HFCVD) system. A mixture of CH4and H2 was introduced during silicon cone formation. AIN films were coated on Si cone arrays using radio frequency (RF) magnetron sputtering system. Scanning electrons microscopy (SEM) was employed to characterize the morphology of silicon cone arrays before and after AIN coating. The field emission characteristics of AIN coated silicon cone arrays, uncoated silicon cone arrays and AlN films were studied and compared, and the silicon cone arrays with AIN coating showed the best enhanced electron emission properties due to the negative electron affinity of AIN coating layer and the high aspect ratio of silicon cone. For AIN coated silicon cone arrays, a slight hysteresis between the upward and downward voltage sweeps was also observed and the field emission currents from AIN coated Si nanocone arrays decreased with the increase of the thickness of AIN films, which could be mainly attributed to the space charge buildup in AIN film with wide band gap.