Effects of vacuum annealing on the optical properties of porous silicon

Abstract

The effects of vacuum annealing on the optical absorption spectra in the visible and infrared ranges, photoluminescence intensity, and concentration of paramagnetic centers in free-standing porous silicon films were investigated in a temperature range of 100-600°C. It was found that heat-induced hydrogen desorption decreased the porous silicon band gap, which suggests that band-gap energy depends on hydrogen coverage of nanoparticles. The annealing also leads to increasing concentration of defects that were identified as silicon dangling bonds. The energy distribution of the dangling-bond states was estimated from the absorption spectrum.

A Study on the Annealing Ambient Effect on the Anti-Pollution Characteristics of Functional Film for PV Modules

“…If the film is annealed while gas is being injected, the impurities to be removed by the annealing may be disturbed by the gas. Therefore, it means that the average light transmittance property improves when the film is annealed in a vacuum [19,20]. Figure 4 shows the average light transmittance measured in a wavelength of 400 to 800 nm of the naturally-dried functional coating film, as well as the functional coating film annealed in H 2 , N 2 , Ar, O 2 , and vacuum ambient.…”

Transport of carriers in metal/porous silicon/c-Si device structures based on oxidized porous silicon

“…16͒ and 85 meV. 17 In addition trap-filled limited SCLC was observed earlier in metal/PS/p-Si structures obtained from moderately 18 and highly doped 19 c-Si substrates and N(E) distributions for such structures were calculated.…”

Photovoltage and photocurrent spectroscopy of luminescent porous silicon

“…Effect of hydrogen content on optical properties of por-Si is known. Authors [30] studied the influence of vacuum annealing on the absorption spectra shape of the free-standing porous silicon films. It was found [30] that vacuum annealing leads to hydrogen effusion and long-wave shift of the absorption edge by approximately to 0.5 eV (from 1.7 to 1.2 eV).…”

“…Authors [30] studied the influence of vacuum annealing on the absorption spectra shape of the free-standing porous silicon films. It was found [30] that vacuum annealing leads to hydrogen effusion and long-wave shift of the absorption edge by approximately to 0.5 eV (from 1.7 to 1.2 eV). Therewith, the absorption edge of the annealed sample was close to the optical absorption edge of crystalline silicon.…”