Dangling bonds (DBs) are common defects in silicon that affect its electronic performance by trapping carriers at the in-gap levels. For probing the electrical properties of individual DBs, a scanning tunneling microscope (STM) is an effective instrument. Here we study transitions between charge states of a single DB on chlorinated and brominated Si(100)-2×1 surfaces in an STM. We observed transitions between positively and negatively charged states of the DB, without the participation of the neutral state. We demonstrated that the (+⁄-) transition occurs when the DB and substrate states are out of equilibrium. This transition is related to the charge neutrality level (CNL), which indicates a change in the DB’s character from donor-like to acceptor-like. The STM voltage at which the (+⁄-) transition took place varied depending to the electrostatic environment of the DB. Our results complement the understanding of the electronic properties of the DBs, and they should be taken into account in applications that use charge manipulation on the DBs.

中文翻译：

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卤化 Si（100） 表面上悬空键的正电荷态和负电荷态之间的转变


悬垂键 （DB） 是硅中的常见缺陷，它通过在间隙内水平捕获载流子来影响其电子性能。为了探测单个 DB 的电学特性，扫描隧道显微镜 （STM） 是一种有效的仪器。在这里，我们研究了 STM 中氯化和溴化 Si（100）-2×1 表面上单个 DB 的电荷态之间的转变。我们观察到 DB 的正电和负电状态之间的转变，没有中性态的参与。我们证明了当 DB 和衬底状态不平衡时，就会发生 （+⁄-） 转变。这种转变与电荷中性水平 （CNL） 有关，它表示 DB 的特性从类似供体变为类似受体。发生 （+⁄-） 转变的 STM 电压根据 DB 的静电环境而变化。我们的结果补充了对 DB 电子特性的理解，在 DB 上使用电荷操纵的应用中应考虑它们。