Tian Yuchen, Ortiz Moreno Ari R, Chipaux Mayeul, Wu Kaiqi, Perona Martinez Felipe P, Shirzad Hoda, Hamoh Thamir, Mzyk Aldona, van Rijn Patrick, Schirhagl Romana
Groningen University, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AW, Netherlands.
Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
Langmuir. 2024 Oct 29;40(43):23007-23017. doi: 10.1021/acs.langmuir.4c03171. Epub 2024 Oct 18.
Diamond is increasingly popular because of its unique material properties. Diamond defects called nitrogen vacancy (NV) centers allow for measurements with unprecedented sensitivity. However, to achieve ideal sensing performance, NV centers need to be within nanometers from the surface and are thus strongly dependent on the local surface chemistry. Several attempts have been made to compare diamond surfaces. However, due to the high price of diamond crystals with shallow NV centers, a limited number of chemical modifications have been studied. Here, we developed a systematic method to investigate the continuity of different local environments with varying densities and natures of surface groups in a single experiment on a single diamond plate. To achieve this goal, we used diamonds with a shallow ensemble of NV centers and introduced a chemical gradient across the surface. More specifically, we used air and hydrogen plasma. The gradients were formed by a low-pressure plasma treatment after masking with a right-angled triangular prism shield. As a result, the surface contained gradually more oxygen/hydrogen toward the open end of the shield. We then performed wide-field relaxometry to determine the effect of surface chemistry on the sensing performance. As expected, relaxation times and thus sensing performance indeed vary along the gradient.
由于其独特的材料特性，钻石越来越受欢迎。被称为氮空位（NV）中心的钻石缺陷能够实现具有前所未有的灵敏度的测量。然而，为了实现理想的传感性能，NV中心需要位于距离表面纳米级的范围内，因此强烈依赖于局部表面化学性质。已经进行了几次比较钻石表面的尝试。然而，由于具有浅NV中心的钻石晶体价格高昂，所研究的化学修饰数量有限。在这里，我们开发了一种系统方法，在单个钻石板上的单个实验中研究具有不同密度和表面基团性质的不同局部环境的连续性。为了实现这一目标，我们使用了具有浅NV中心集合的钻石，并在整个表面引入了化学梯度。更具体地说，我们使用了空气和氢等离子体。梯度是通过用直角三棱柱屏蔽进行掩膜后进行低压等离子体处理形成的。结果，朝着屏蔽的开口端，表面逐渐含有更多的氧/氢。然后，我们进行了宽场弛豫测量，以确定表面化学性质对传感性能的影响。正如预期的那样，弛豫时间以及传感性能确实沿着梯度变化。
