Growth of ultraclean, isotopically controlled diamond films and nanoparticles with well defined single defects and atomically smooth surfaces

我们打算利用微波辅助化学气相沉积（MWCVD）技术开发和研究超纯和相应定制掺杂的单晶金刚石层，以及金刚石引脚二极管和纳米金刚石晶体在量子光学中的应用。单氮空位（NV）和单硅空位（SiV）中心将通过生长或注入到金刚石针脚二极管结构中，目的是实现电激单光子发射。为了增强光输出，将使用电子束光刻和ICP蚀刻将引脚二极管结构成纳米柱阵列（直径约200纳米）。对于电接触，柱子将嵌入到SU-8-PDMS矩阵中（折射率为1.4，而金刚石为2.4）。在水平的n面，石墨烯或氧化铟锡（ITO）将被用作透明和导电的触点，以单独处理柱子。利用RIE和反射镜涂层将p型掺杂侧变薄，以增强和直接发光。由于NV中心在许多情况下被植入表面附近，因此需要固定表面费米能级以稳定NV中心的电荷状态。这将通过沉积几纳米厚的金刚石层来实现。这些薄层将被磷和氮掺杂，在其中一个优化的掺杂密度将被实验确定。在这方面，在前一个项目中建造的新的MWCVD反应器将具有特别重要的意义。新的mwcvd反应器提供了在外延过程中提取金刚石衬底的可能性，因此可以通过完全交换工艺气体来实现突然的原子跃迁（“δ掺杂”）。新的反应器还将用于沉积超纯金刚石层。作为离子注入的一种替代方法，我们将研究采用气相掺杂的方法将稀土元素掺入到金刚石中。这样做的目的是在红外光谱区（> 1200nm）找到nv中心的替代品。我们将在cvd金刚石生长过程中使用金属有机镧系化合物，如三异丙基环戊二烯铒，应用原位气相掺杂方法。与nv中心相比，SiV中心表现出窄带宽发射。通过MWCVD将siv中心与目标结合到金刚石纳米颗粒中，用于光子结构。在项目过程中，金刚石纳米颗粒通过机械化学方法从超纯金刚石中制造出来，并通过等离子体蚀刻特别优化了它们的几何特性。目标是去除尖锐的边缘，产生10到50纳米之间的颗粒。这些粒子应在lAF中掺杂稀土原子、SiV和NV中心。最后，通过表面功能化可以稳定纳米金刚石粒子发射中心的光谱特征。

We intend to develop and to investigate ultra-pure and accordingly custom doped singlecrystalline diamond layers, as well as diamond pin diodes and nanodiamond crystals forapplications in quantum optics using microwave assisted chemical vapor deposition (MWCVD). Single nitrogen-vacancy (NV) and silicon vacancy (SiV) centers will be incorporated either by growth or implantation into diamond pin-diode structures with the aim for electrical stimulated single photon emission. In order to enhance the light output the pin-diodes will be structured into arrays of nanopillars (diameter around 200 nm) using E-beam lithography and ICP etching. For electrical contacting the pillars will be embedded into a SU-8-PDMS matrix (refractive index 1.4 in contrast to diamond with 2.4). On the leveled n-side graphene or indium tin oxide (ITO) will be applied as transparent and conductive contacts, to address the pillars individually. The p-type doped side of the pin-diode will be thinned using RIE and mirror coated, to enhance and direct light emission.Because NV-centers are implanted in many cases near to the surface, the surface Fermi level needs to be fixed to stabilize the charge state of the NV" center. This will be achieved by depositions of a few nanometers thick diamond layers. These thin layers will be doped with phosphorous and nitrogen, at which an optimized doping density will be determined experimentally. In this connection the new MWCVD reactor which was built in the previous project will be of special importance. The new MWCVD-reactor offers the possibility to extract the diamond substrate during epitaxy, thus abrupt, atomically transitions ("delta doping") can be realized by complete exchange of process gases. The new reactor will also be used to deposit ultra-pure diamond layers.As an alternative to ion-implantation we will study the incorporation of rare earth elements in diamond using gas phase doping. This will be done with the objective to identify alternatives to the NV-center in the IR spectral region (>1200 nm). We will apply an in situ gas phase doping approach during CVD-diamond growth using metal organic lanthanide compounds such as tris isopropyl cyclopentadienyl erbium.In contrast to the NV-center, the SiV center exhibits a narrow bandwidth emission. SiV-centers will be incorporated into diamond nanoparticles by MWCVD with the target to use them in photonic structures. In the course of the project, diamond nanoparticles are created from ultra-pure diamond by mechanochemical methods and their geometric properties are specifically optimized by plasma etching. The objective is to remove sharp edges and produce particles between 10 and 50 nm.These particles should be doped with rare earth atoms, SiV and NV centers at lAF. Finally, the spectral characteristics of the emission centers in nano-diamond particles will be stabilized by surface functionalization.