We report on tuning the carrier capture events at a single dangling bond (DB) midgap state by varying the substrate temperature, doping type, and doping concentration. All-electronic time-resolved scanning tunneling microscopy (TR-STM) is employed to directly measure the carrier capture rates on the nanosecond time scale. A characteristic negative differential resistance (NDR) feature is evident in the scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) measurements of DBs on both n- and p-type doped samples. We find that a common model accounts for both observations. Atom-specific Kelvin probe force microscopy (KPFM) measurements confirm the energetic position of the DB’s charge transition levels, corroborating STS studies. We show that under different tip-induced fields the DB can be supplied with electrons from two distinct reservoirs: the bulk conduction band and/or the valence band. We measure the filling and emptying rates of the DBs in the energy regime where electrons are supplied by the bulk valence band. We show that adding point charges in the vicinity of a DB shifts observed STS and NDR features due to Coulombic interactions.

中文翻译：

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在单个硅原子间隙状态下解析和调整载流子捕获速率

我们报告了通过改变衬底温度，掺杂类型和掺杂浓度来调整单悬键（DB）中带隙状态下的载流子俘获事件。全电子时间分辨扫描隧道显微镜（TR-STM）用于直接测量纳秒级的载流子捕获率。在n型和p型掺杂样品上的DB的扫描隧道显微镜（STM）和扫描隧道光谱（STS）测量中，具有明显的负负电阻（NDR）特征。我们发现一个共同的模型解释了这两个观察结果。原子特异性开尔文探针力显微镜（KPFM）测量证实了DB电荷跃迁水平的高能位置，从而证实了STS研究。我们表明，在不同的尖端感应场下，可以为DB提供来自两个不同储层的电子：体导带和/或价带。我们测量在由大价带提供电子的能量状态下，DB的填充和排空速率。我们显示，由于库仑相互作用，在DB附近添加点电荷会改变观察到的STS和NDR功能。