TOF-LEIS spectra of Ga/Si: Peak shape analysis

Decoupling the Two Roles of Ga Droplets in the Self-Catalyzed Growth of GaAs Nanowires on SiOx/Si(111) Substrates

“…As indicated in Figure 2a, the number density of Ga droplets decreased monotonically by 3 orders of magnitude, from 10 10 cm −2 to 10 7 cm −2 , with increasing T d from 450 to 590 °C (see the corresponding AFM images in Figure S4 of the Supporting Information). The reason for this behavior is the increased surface diffusivity of Ga adatoms at higher T d 31,37,38 as well as the lower sticking of Ga at T d > 500 °C according to Figure 2c (number density of Ga atoms vs T d ). Like in our analysis above, the low sticking of Ga adatoms on the substrate at high T d can be attributed to desorption of Ga and/or Ga 2 O from the SiO x surface.…”

Self-limiting cyclic growth of gallium droplets on Si(111)

“…This result indicates that the mechanism of coarsening is also the same in the low-temperature region and that it is not affected by the external deposition flux. The value of 0.48 eV represents the activation energy of diffusion, since the mechanism of growth was determined previously as being diffusion-limited [10]. In figure 2(a) the dependence of the droplet base area on the deposition temperature is shown.…”

“…The estimated error of the temperature measurement is ±20 • C. Ga was deposited continuously at specific substrate temperatures and thus the clusters grew under an external flux of atoms. This flux was kept the same in all experiments and corresponded to a room temperature Ga deposition rate of 0.18 monolayer (ML) min −1 , calibrated previously by lowenergy ion scattering [10] and a quartz crystal thickness meter. After deposition at a specific temperature and cooling the samples down they were characterized ex situ by atomic force microscopy (AFM) in the contact mode (AutoProbe CP-R, Veeco) using a tip with the nominal diameter <10 nm.…”

“…In our previous work we have found that the Ga/Si system exhibits a pronounced 3D island growth even at room temperature. With increasing substrate deposition temperature the droplets become larger because of the enhanced mobility of Ga adatoms on the surface [10].…”

Real-time observation of self-limiting SiO2/Si decomposition catalysed by gold silicide droplets

“…The analysis was carried out in a home-built complex ultra-high vacuum (UHV) system 38 employing a home-made ToF-LEIS spectrometer 39,40 Omicron DAR400 X-ray source, and an EA125 electron energy spectrometer. Scanning probe experiments were carried out using a commercial ambient scanning probe microscope (ICON Dimension, Bruker) in tapping mode using a calibrated symmetrical cantilever RTESPA-300 with an 8 nm tip radius.…”