Vacancy

OutlineWettability influenced by vacancy

Vacancy Detect Instrument

X-ray photoelectron spectroscopy (XPS)

X-ray Absorption Spectroscopy (XAS)

Scanning Electron Microscopy (SEM-CL)

Transmission Electron Microscopy (TEM)

Scanning (STM)

Cataluminescence

Vacancy on Surface

surface structure and composition

hydrophilicity

examine surface property

X-ray photoelectron spectroscopy (XPS)

Principle of XPS

𝑬𝒑𝒉=𝒉𝝂−𝑬𝒃−𝝓: kinetic energy of the photoelectron : Planck constant : frequency of X-ray : binding energy of electron on inner orbit: work function dependent on both the spectrometer and the material

Chemical Shift of XPS

unneutral atom due to different electronegativity

- the more electronegative

local negative 𝑬𝒑𝒉↑ ,𝑬𝒃↓

- the less electronegative

local positive 𝑬𝒑𝒉↓ ,𝑬𝒃↑

XPS Spectrum (ZnO)

With the area of each signal,one can compare ratio of theconcentration

XPS Spectrum at Different Annealing Temperature

- as the annealing temperature increasing

ratio of vacancy rises

- in a vacuum environment

more easier to form vacancy

Hydrophilicity and Vacancy

with the concentration of vacancy increase

the surface will be more hydrophilic