以氧氣場效蝕刻法製備鈮奈米針

Abstract

我們提出在超高真空環境下多晶鈮針的簡易的針型修復技術。這種針型修復技術是基於在場離子顯微鏡的操作下空間性的控制氧氣與鈮表面原子發生反應。限制場效蝕刻反應發生在針柄處使我們得以製作鈮奈米針。從FIM成像偏壓下降以及針尖部位FIM影像面積縮減可證實奈米針尖形成。我們場效蝕刻鈮針在三個不同的樣品溫度(25K、50K、80K) 。然後我們比較其蝕刻效率與影像品質。 我們量測蝕刻後針尖的場發射電子電流並繪製F-N圖。F-N圖顯示場效蝕刻後針尖的針型在熱處理後會發生變化。我們也對30分鐘內鈮奈米針的場發射電流穩定度進行量測。當場發射電子電流434Pa時，不穩定度在10%以下｡

We present a straightforward modification technique for poly-crystal niobium tips in UHV. The modification technique is based on spatially controlling the reaction of oxygen gas with the surface atoms of a niobium tip in a field ion microscope (FIM). Confining this field-assisted etching reaction to the shank has enabled us to produce niobium nano- tips. Nano-tip formation is evident from the decrease in the FIM imaging voltage and the decrease in the apex area. We field-assisted etch niobium tip at three different temperature (25K，50K，80K). Then we compare the etching efficiency and FIM image quality. We measure the field emission electron current form the etched nano-tip and illustrate the F-N plot. The F-N plot shows that the shape of the etched tip will change after thermal treatment. We also measure the stability of the field emission current from the etched niobium nano-tip in 30 minute. When the emission electron current is 434pA, the instability is less than 10%.