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锐钛矿晶体金刚石层，以及金刚石pin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）和硅空位（SiV）中心将通过生长或注入到金刚石pin二极管结构中，目的是电刺激单光子发射。为了增强光输出，pin二极管将使用电子束光刻和ICP蚀刻构造成纳米柱阵列（直径约200 nm）。为了电接触，柱将嵌入SU-8-PDMS基质（折射率1.4，与具有2.4的金刚石形成对比）中。在平整的n侧上，石墨烯或氧化铟锡（ITO）将被用作透明和导电接触，以单独寻址柱。pin二极管的p型掺杂侧将使用RIE和镜面涂覆来减薄，以增强和引导光发射。因为NV中心在许多情况下靠近表面注入，所以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。这些薄层将掺杂有磷和氮，在此，将通过实验确定优化的掺杂密度。在这方面，在上一个项目中建造的新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（“delta掺杂”）。新的反应器也将用于存款超纯金刚石层。作为离子注入的替代方案，我们将研究使用气相掺杂在金刚石中掺入稀土元素。这样做的目的是识别IR光谱区域（>1200 nm）中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（如三异丙基铒）采用原位气相掺杂方法。与NV中心相比，SiV中心表现出窄带宽的发射。SiV中心将通过MWCVD并入金刚石纳米颗粒中，目标是将它们用于光子结构中。在该项目的过程中，金刚石纳米颗粒是通过机械化学方法从超纯金刚石中产生的，它们的几何特性是通过等离子体蚀刻进行专门优化的。目标是去除尖锐边缘并产生10和50 nm之间的颗粒。这些颗粒应在lAF处掺杂稀土原子、SiV和NV中心。最后，纳米金刚石颗粒的发射中心的光谱特性将通过表面功能化来稳定。

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.