Ring charging of a single silicon dangling bond imaged by noncontact atomic force microscopy

Abstract

The electrostatic properties of defects of the Si( 111)-( √ 3 × √ 3)R • 30 surface are studied using noncontact atomic force microscopy and Kelvin probe force microscopy with subnanometer resolution and subelementary charge sensitivity. We identify nonparabolicities in the frequency-voltage spectroscopy of single dangling bonds (DBs), which reveal the transition from empty to single electronically occupied DBs. Kelvin probe imaging reveals that the DB charging, however, occurs with a ring shape with radius ∼500 pm located along the circumference of the DB wave function. The ring charging is explained by a tip-induced modulation of the hole recombination rate at the DB-substrate interface.

Single-dopant band bending fluctuations in MoSe$_2$ measured with electrostatic force microscopy

“…The nonparabolicity in the force F ts which arises due to the nonlinearity in surface potential V S leads to a nonparabolic fm-AFM frequency shift above MoSe 2 (Figure 1c). Recently, similar nonparabolicities have been reported in other systems measured with fm-AFM, including dangling bonds on Si(111) [5] and pentacene on KBr [18]. Reference measurements on SiO 2 , in contrast, show a parabolic frequency shift as a function of bias.…”

“…Understanding these systems is critical for the study of single-electron physics, and two-state systems are of particular relevance for emerging quantum information technology. In semiconducting devices such as photovoltaics, transistors, and diodes, individual charge states such as dangling bonds [5], individual dopants [6], and defects [7] are not electrically isolated from their environment, and it is critical to understand their effects on the global electronic structure, in particular device efficiency and noise. In this work, we measure single dopant fluctuations which give rise to variations in the surface potential of a mesoscopic metal-insulator-semiconductor (MIS) capacitor device.…”

Investigation of semiconductor properties of Co/Si(111)-7 × 7 by AFM/KPFS

“…Kelvin probe force microscopy (KPFM) reflects the local work function difference among surface structures; the charge distribution on the semiconductor surface can be revealed [25][26][27][28][29]. The combination of NC-AFM and KPFM is wildly used to investigate charge transport on semiconductor surfaces [30][31][32][33][34][35][36][37]. Kelvin probe force spectroscopy (KPFS) is based on AFM and KPFM, which can be used to identify the charge state and control the charge transfer [32,33].…”

“…Kelvin probe force spectroscopy (KPFS) is based on AFM and KPFM, which can be used to identify the charge state and control the charge transfer [32,33]. The KPFS method has been applied to identify dopants, defects, and dangling bonds, among others [34][35][36][37]. Schwarz et al obtained the distribution of doped atoms on a gallium arsenide (InAs)(110) surface on the basis of AFM findings, and the bias spectroscopy shows a nonparabolic property on the dopant site, revealing the accumulation, depletion, and reversion layers on the semiconductor [34].…”

Single-dopant band bending fluctuations in MoSe2 measured with electrostatic force microscopy

“…Understanding these systems is critical for the study of single-electron physics, and two-state systems are of particular relevance for emerging quantum information technology. In semiconducting devices, individual charge states such as dangling bonds [5], individual dopants [6], and defects [7] are not electrically isolated from their environment, and it is necessary to understand their effects on the global electronic structure, in particular device efficiency and noise. In this work, we measure single dopant fluctuations which give rise to variations in the surface potential of a mesoscopic metal-insulatorsemiconductor (MIS) capacitor device.…”