Single Color Centers in Silicon Carbide: electro-optical access via epitaxial graphene

宽禁带半导体中的色心物理已经引起了人们的极大关注，因为它提供了研究基本量子现象的途径。与钻石中典型的NV中心相比，碳化硅(SIC)中的颜色中心具有类似的特性，并具有完全成熟的碳化硅器件制造技术的额外好处。该方案的目标是同时对碳化硅中的色心进行电学和光学表征，特别是本征缺陷。对于它们的产生，我们开发了一种结合离子注入和优化退火法的方法，从而可以获得最小的SiC(0001)表面下的缺陷浓度，最终目标是获得单个缺陷。(0001)表面将配备外延生长的石墨烯电极，从而产生空间电荷区，在该空间电荷区中可以对所研究的缺陷进行静电控制。特别是，人们可以随意地用电荷填充或清空缺陷。结合我们的专利外延单片碳化硅/石墨烯晶体管，我们将进一步优化漏电流深能级瞬变光谱，目标是在电信号中实现单缺陷灵敏度。同时，透明的石墨烯电极允许光学访问非常相同的缺陷，我们将使用共焦显微镜在可见光和红外光谱范围内对其进行光谱分析。我们期望通过在同一颜色中心的电和光控制以及电和光表征来深入了解激发光谱，从而在电和光激发之间架起一座桥梁。这种改进的缺陷分析方法对碳化硅电子器件的开发具有重要意义。它进一步提供了在这个强大和成熟的材料系统中建立具有电子控制的单光子源的机会，这为例如高灵敏度传感器铺平了道路。

The physics of color centers in wide bandgap semiconductors has attracted substantial attention as it provides access to fundamental quantum phenomena. Compared to the prototypic NV center in diamond, color centers in silicon carbide (SiC) exhibit similar properties with the additional benefit of a fully mature technology for SiC device fabrication. The proposal targets the simultaneous electrical and optical characterization of color centers, in particular intrinsic defects, in SiC. For their generation we develop a methodology that combines ion implantation and optimized annealing such that smallest defect concentrations underneath the SiC (0001) surface can be achieved with the ultimate goal of access to single defects. The (0001) surface will be equipped with epitaxially grown graphene electrodes, such that a space charge region results, in which the defect under investigation can be electrostatically controlled. In particular, one can fill or empty the defect with charge at will. In connection with our patented epitaxial monolithic SiC/Graphene transistors, we will further optimize the Drain-Current Deep-Level Transient Spectroscopy with the goal of single-defect sensitivity in the electrical signal. Simultaneously, the transparent graphene electrodes allow optical access to the very same defect, on which we will perform spectroscopy in the visible and infrared spectral range using a confocal microscope. We expect via the combined electrical and optical control as well as the electrical and optical characterization at the very same color center a deep understanding of the excitation spectra and, thus, build a bridge between electrical and optical excitation. This refined methodology of defect analysis has significant importance for SiC electronic device developments. It further offers an opportunity to build single-photon sources with electrical control in this powerful and mature material system, which paves the way, for example, for highly sensitive sensors.