因此，噴金并非不導電樣品的優選方法。低真空模式同樣適用于不導電樣品。低真空模式在處理非導電樣品時具有多個優勢，它可以實現無電荷成像還可以提高材料對比度，并使用更高的電子束流進行化學分析。低真空掃描電鏡技術是通過在樣品室內通入少量的氣體/水蒸氣實現的。少量的空氣進入掃描電鏡樣品室，在電子和氣體分子之間通過碰撞產生正離子，當這些正離子電流達到樣品完全抵消全部負電荷時，也就是出現了所謂的電荷平衡，從而消除了樣品表面的荷電效應。
上圖1~4是纖(xian)維(wei)樣(yang)品在不噴(pen)金，低真空模(mo)式下(xia)拍攝的(de)圖片(pian)。1、2為(wei)背散射(she)圖像(xiang)(xiang)，3、4為(wei)二次(ci)電子圖像(xiang)(xiang)，在兩種圖像(xiang)(xiang)模(mo)式下(xia)，Axia均表現出優異的(de)成像(xiang)(xiang)功(gong)能。AxiaChemiSEM提(ti)供的(de)低真空模(mo)式，可(ke)調節(jie)壓力到(dao)zui高150Pa，支持各(ge)種不同(tong)的(de)樣(yang)品。
然(ran)而(er)，低(di)真空(kong)模(mo)式(shi)也并非始終是(shi)優選(xuan)，在(zai)突出(chu)樣(yang)(yang)品(pin)表面(mian)細節時(shi)，需要較低(di)的(de)(de)(de)(de)(de)(de)著陸(lu)(lu)能 量(liang)，否則這(zhe)些細節會隨著高(gao)加(jia)速電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)而(er)變平(ping)。例如觀察(cha)纖(xian)(xian)維制品(pin)時(shi),不(bu)經過鍍導(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)膜,看(kan)原(yuan)始形(xing)態(tai),將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)下(xia)調(diao)到1kV或以下(xia),既滿足樣(yang)(yang)品(pin)少放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian),又有足夠的(de)(de)(de)(de)(de)(de)信號強度(du)(du)(du)。圖5~8為(wei)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)下(xia)的(de)(de)(de)(de)(de)(de)纖(xian)(xian)維形(xing)貌(mao),可(ke)清楚看(kan)到纖(xian)(xian)維形(xing)態(tai)的(de)(de)(de)(de)(de)(de)差異,與高(gao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)下(xia)的(de)(de)(de)(de)(de)(de)圖像(xiang)相比(bi)，纖(xian)(xian)維表面(mian)突顯出(chu)更細微(wei)的(de)(de)(de)(de)(de)(de)結構,表面(mian)的(de)(de)(de)(de)(de)(de)顆(ke)粒感變得更為(wei)明顯。通過對比(bi)，我們可(ke)以看(kan)到，Axia在(zai)1KV電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)下(xia)的(de)(de)(de)(de)(de)(de)成像(xiang)效果(guo)絲毫不(bu)落后于場發(fa)射(she)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)下(xia)的(de)(de)(de)(de)(de)(de)成像(xiang)效果(guo)。AxiaChemiSEM提供了(le)有效的(de)(de)(de)(de)(de)(de)減少電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷策略，允(yun)許(xu)在(zai)高(gao)真空(kong)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)束(shu)減速(BD)模(mo)式(shi)下(xia)為(wei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)束(shu)敏(min)感樣(yang)(yang)品(pin)成像(xiang)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)束(shu)減速是(shi)一種(zhong)光學模(mo)式(shi)，其中用施加(jia)在(zai)樣(yang)(yang)品(pin)架(jia)上(shang)的(de)(de)(de)(de)(de)(de)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)位使樣(yang)(yang)品(pin)產(chan)生偏(pian)壓(ya)，使原(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)在(zai)著陸(lu)(lu)前(qian)減速。因為(wei)加(jia)速電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)高(gao)于著陸(lu)(lu)能 量(liang)，所(suo)以可(ke)提高(gao)分(fen)辨(bian)率(lv)。此外,電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)束(shu)減速模(mo)式(shi)能夠檢測到幾乎平(ping)行(xing)于樣(yang)(yang)品(pin)表面(mian)的(de)(de)(de)(de)(de)(de)低(di)角度(du)(du)(du)背(bei)散(san)射(she)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(低(di)角度(du)(du)(du)BSE)，從(cong)而(er)提高(gao)了(le)表面(mian)的(de)(de)(de)(de)(de)(de)拓撲結構。工業(ye)和先(xian)進的(de)(de)(de)(de)(de)(de)材料(liao)表征(zheng)通常會處理未知材料(liao)和應對各種(zhong)各樣(yang)(yang)的(de)(de)(de)(de)(de)(de)要求。因此，全面(mian)的(de)(de)(de)(de)(de)(de)解決(jue)方案、分(fen)析功能和處理絕(jue)緣或電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)束(shu)敏(min)感樣(yang)(yang)品(pin)的(de)(de)(de)(de)(de)(de)能力顯得尤為(wei)重要。全新的(de)(de)(de)(de)(de)(de)AxiaChemiSEM具有全面(mian)的(de)(de)(de)(de)(de)(de)性能，可(ke)為(wei)不(bu)同類型(xing)材料(liao)的(de)(de)(de)(de)(de)(de)表征(zheng)提供信息。
參考文獻：
[1]周廣榮.低真空掃描電鏡技術在材料研究中的應用[J].分析儀器,2012(06):39-42.
[2]吳東曉,張大同,郭莉萍.掃描電鏡低電壓條件下的應用[J].電子顯微
報,2003(06):655-656.
