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

宽带隙半导体中色心的物理学已经吸引了大量的关注，因为它提供了对基本量子现象的访问。与金刚石中的原型NV中心相比，碳化硅（SiC）中的色心表现出类似的特性，并具有用于SiC器件制造的完全成熟的技术的额外益处。该提案的目标是在SiC中同时进行色心的电学和光学表征，特别是本征缺陷。对于它们的生成，我们开发了一种方法，该方法结合了离子注入和优化退火，使得SiC（0001）表面下的最小缺陷浓度可以实现与访问单个缺陷的最终目标。（0001）表面将配备有外延生长的石墨烯电极，使得产生空间电荷区域，其中可以静电控制所研究的缺陷。特别地，人们可以随意地用电荷填充或清空缺陷。结合我们获得专利的外延单片SiC/石墨烯晶体管，我们将进一步优化漏极电流深能级瞬态谱，目标是实现电信号中的单缺陷灵敏度。同时，透明的石墨烯电极允许光学访问非常相同的缺陷，我们将使用共聚焦显微镜在可见光和红外光谱范围内进行光谱分析。我们期望通过组合的电学和光学控制以及在同一色心的电学和光学表征，深入了解激发光谱，从而在电学和光学激发之间建立桥梁。这种改进的缺陷分析方法对SiC电子器件的发展具有重要意义。它还提供了在这种强大而成熟的材料系统中构建具有电气控制的单光子源的机会，例如，为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.