Excellent field emission from ultrafine vertically aligned nanorods of NdB6 on silicon substrate

Abstract

Rare earth hexaboride based display devices have attracted significant research interest because of low work function and interesting field emission properties. In the present manuscript, the synthesis of nanostructured neodymium hexaboride (NdB6) has been carried out via low-temperature process using ultrafine nanorods of Nd(OH)3 and NaBH4 as starting material. The Nd(OH)3 were reacted with NaBH4 at 1000 °C in an inert atmosphere at a variable heating rate (40 °C/h and 250 °C/h). The low heating rate (40 °C/h) leads to the formation of ultrafine nanorods of NdB6 (10 nm × 100 nm), while at the high heating rate ultrafine nanocubes (15–20 nm) were obtained. Further, the as-obtained nanocubes and nanorods were deposited on Si- substrate using the spin-coating process to fabricate NdB6 film. Surface analysis of deposited NdB6 film shows that nanorods of NdB6 were vertically aligned. Field emission study of vertically aligned NdB6 nanorods shows low turn-on field (<4.5 V/μm) and the highest enhancement factor (β = 2263) ever reported for NdB6. The reason behind the high field enhancement factor (two fold higher than the maximum reported (β = 1037)) is due to ultrafine vertical orientated nanorods.