Singh Sonal, Catledge Shane A
J Appl Phys. 2013 Jan 28;113(4):44701. doi: 10.1063/1.4783958. Epub 2013 Jan 22.
Fluorescent nanodiamonds were produced by incorporation of silicon-vacancy (Si-V) defect centers in as-received diamonds of averaged size ∼255 nm using microwave plasma chemical vapor deposition. The potential for further enhancement of Si-V emission in nanodiamonds (NDs) is demonstrated through controlled nitrogen doping by adding varying amounts of N(2) in a H(2) + CH(4) feedgas mixture. Nitrogen doping promoted strong narrow-band (FWHM ∼ 10 nm) emission from the Si-V defects in NDs, as confirmed by room temperature photoluminescence. At low levels, isolated substitutional nitrogen in {100} growth sectors is believed to act as a donor to increase the population of optically active (Si-V)(-) at the expense of optically inactive Si-V defects, thus increasing the observed luminescence from this center. At higher levels, clustered nitrogen leads to deterioration of diamond quality with twinning and increased surface roughness primarily on {111} faces, leading to a quenching of the Si-V luminescence. Enhancement of the Si-V defect through controlled nitrogen doping offers a viable alternative to nitrogen-vacancy defects in biolabeling/sensing applications involving sub-10 nm diamonds for which luminescent activity and stability are reportedly poor.
通过微波等离子体化学气相沉积法，在平均尺寸约为255纳米的原始钻石中引入硅空位（Si-V）缺陷中心，从而制备出荧光纳米金刚石。通过在H₂ + CH₄原料气混合物中添加不同量的N₂进行可控氮掺杂，证明了纳米金刚石（NDs）中Si-V发射进一步增强的潜力。室温光致发光证实，氮掺杂促进了纳米金刚石中Si-V缺陷的强窄带（半高宽约10纳米）发射。在低水平时，{100}生长扇区中孤立的替代氮被认为起到施主作用，以牺牲光学非活性的Si-V缺陷为代价，增加光学活性（Si-V）⁻的数量，从而增加该中心观察到的发光。在高水平时，聚集的氮会导致金刚石质量下降，出现孪晶现象，并主要在{111}面上增加表面粗糙度，导致Si-V发光猝灭。在涉及小于10纳米的钻石的生物标记/传感应用中，通过可控氮掺杂增强Si-V缺陷为氮空位缺陷提供了一种可行的替代方案，据报道，对于这些应用，氮空位缺陷的发光活性和稳定性较差。
