The origin of spectral distortion in electric field modulation spectroscopy based on scanning tunneling microscopy

Nanoscale-resolved near-infrared photoabsorption spectroscopy and imaging of individual gallium antimonide quantum dots

“…[12][13][14][15][16] The origin of the lowenergy band, a magnified image of which is shown in the inset, can be attributed to photoabsorption by the GaSb dots. The former threshold corresponds to the indirect photoabsorption edge of the Si substrate, as reported elsewhere.…”

“…9,10,13,15 Measurements under tunneling conditions can cause signal fluctuations as a result of thermal drift, and Figure 2(d) shows the STM-EFMS spectra obtained from the same dots as those in Figs. 9,10,13,15 Measurements under tunneling conditions can cause signal fluctuations as a result of thermal drift, and Figure 2(d) shows the STM-EFMS spectra obtained from the same dots as those in Figs.…”

“…[12][13][14][15][16] The sample transferred to the STM stage was probed at 98 K with a Pt-Ir tip for the STM-PAS measurements with irradiation by wavelength-tunable light from a halogen lamp, whose wavelength was swept by a grating monochromator (TRIAX 320; Horiba Jobin Yvon) with a spectral resolution of 0.0017 eV. Oxidation of the surface of the sample, which inevitably occurs during the exsitu sample transfer, is beneficial for the present STM-PAS measurements because it removes surface states whose presence would suppress the generation of a large SPV as a result of Fermi-level pinning.…”

“…Defects and impurities localized within the nanoscale dots can generate unintentional energy states that have deleterious effects, for example, by acting as centers for electron-hole generation and recombination. 9,10,13,15 These two schemes have a number of features in common. [9][10][11][12][13][14][15][16] One scheme for STM-PAS, which is used in the present study, is called STM photomodulated current spectroscopy (STM-PMCS); 11,12,17 a second scheme is called STM electric field modulation spectroscopy (STM-EFMS).…”

Self-Assembled Epitaxial Growth of High Density β-FeSi2 Nanodots on Si (001) and Their Spatially Resolved Optical Absorption Properties

“…The details of the STM-EFMS measurements are described in previous papers. 16,22 Iron silicides were formed by codeposition of 4-ML Fe and 8-ML Si at various temperatures, T co of RT-500 °C, after 1-ML Si was deposited on ∼0.3 nm ultrathin SiO 2 films at ∼670 °C (Si predeposition). Figure 1a,b show RHEED patterns of the iron silicides formed by codeposition at 500 °C and RT, respectively.…”