Visualizing charge transport in silicon nanocrystals embedded in SiO2 films with electrostatic force microscopy

Abstract

In this work, we report a mapping of charge transport in silicon nanocrystals (nc-Si) embedded in SiO2 dielectric films with electrostatic force microscopy. The charge diffusion from chargednc-Si to neighboring uncharged nc-Si in the SiO2 matrix is found to be the dominant mechanism for the decay of the trapped charge in the nc-Si. The trapped charge and the charge decay have been determined quantitatively from the electrical force measurement. An increase in the area of the charge cloud due to the charge diffusion has been observed clearly. In addition, the blockage and acceleration of charge diffusion by the neighboring charges with the same and opposite charge signs (i.e., positive or negative), respectively, have been observed.

Charge-Selective Raman Scattering and Fluorescence Quenching by “Nanometal On Semiconductor” Substrates

“…In addition, EFM has been used in more specific cases, some of which include imaging the voltage characteristics of working microelectronic devices and in charge injection and detection of localized charge in nanostructures 52 . Furthermore, EFM has also extended to study the charge transport mechanisms in single NP embedded in insulating thin films [53][54][55] .…”

Selective X‐ray analysis of electron localizing sites using capacitance or electrostatic force

“…On the other hand, the probe method in which X-rays are introduced into scanning probe microscope can confine the probing area of the X-ray-induced photoionization. The scanning probe microscopes used for spot detection of capacitance and electrostatic force are known as SCM (scanning capacitance microscope) [6] and EFM (electrostatic force microscope) [7], respectively. Many stand-alone SCM and EFM without X-ray source are commercially available, and have been applied to evaluation of electrical characteristics or catalyst performance on microscopic surface areas.…”

Charging effect in silicon nanocrystals observed by electrostatic and Kelvin-probe force microscopy

“…In EFM, the tip's cantilever resonance frequency would change due to the Coulomb force gradient and its shift value f was recorded when applying a constant dc voltage V EFM to the tip [5]. In KPFM, however, the feedback circuit would eliminate the electric force by adjusting a dc & ac compensatory voltage V dc +V ac Sin(t) to the tip and output the surface potential signals (equal to V dc ) [7].…”

“…In the past several years, electrical modes of atomic force microscopy (AFM) such as electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM) have been widely applied to observe the charging effect in metal or semiconductor nanostructures [4][5][6][7][8], but few works have combined these two techniques to have a comparative study.…”