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

我们打算开发和研究使用微波辅助化学气相沉积(MWCVD)在量子光学中应用的超纯和相应的定制掺杂单晶金刚石层，以及金刚石引脚二极管和纳米金刚石晶体。单个氮空位(NV)和硅空位(SIV)中心将通过生长或注入到金刚石销钉二极管结构中，以实现电刺激单光子发射。为了提高光输出，将利用电子束光刻和电感耦合等离子体刻蚀技术将PIN二极管结构成直径约200 nm的纳米管阵列。对于电接触，柱子将嵌入SU-8-PDMS矩阵(折射率为1.4，而钻石为2.4)。在平整的n侧石墨烯或氧化铟(ITO)将被用作透明和导电触点，以单独寻址柱子。PIN二极管的p型掺杂一侧将使用RIE和镜面镀膜进行减薄，以增强和引导光发射。由于许多情况下NV中心被植入到靠近表面的地方，因此需要固定表面费米能级来稳定NV“中心的电荷状态。这将通过沉积几纳米厚的钻石层来实现。在这些薄层中掺入磷和氮，最佳掺杂浓度将通过实验确定。在这方面，前一个项目中建造的新的MWCVD反应堆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，因此可以通过工艺气体的完全交换来实现突然的原子转变(“增量掺杂”)。新的反应堆还将用于沉积超纯金刚石层。作为离子注入的替代方案，我们将研究通过气相掺杂在金刚石中掺入稀土元素。这样做的目的是为了确定红外光谱区域(&gt；1200 nm)中NV中心的替代方案。我们将在CVD-金刚石生长过程中应用原位气相掺杂的方法，使用三异丙基环戊二烯基铒等金属有机稀土化合物。与NV中心相反，SIV中心表现出窄带宽发射。SIV中心将通过MWCVD被结合到钻石纳米颗粒中，目标是将它们用于光子结构。在该项目的过程中，通过机械力化学方法从超纯钻石中制备出金刚石纳米颗粒，并通过等离子体刻蚀对其几何性质进行了具体优化。目标是去除尖锐的边缘，产生10到50 nm之间的粒子。这些粒子应该在LAF处掺杂稀土原子、SiV和NV中心。最后，纳米金刚石颗粒中发射中心的光谱特性将通过表面功能化得到稳定。

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.