| AVS 54th International Symposium | |
| Advanced Surface Engineering | Tuesday Sessions |
| Session SE-TuM |
| Session: | Glancing Angle Deposition |
| Presenter: | I.Z. Indutnyy, V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine |
| Authors: | I.Z. Indutnyy, V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine V.A. Dan’ko, V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine I.Yu. Maidanchuk, V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine V.I. Min’ko, V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine P.E. Shepeliavyi, V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine |
| Correspondent: | Click to Email |
Nanocrystalline silicon (nc-Si) embedded in SiOx matrix recently have attracted much interest due to perspective of application in optoelectronics and photonics. One of the methods that allow forming nanocomposite Si-SiOx films is vacuum deposition of amorphous SiOx with further anneal in vacuum or inert atmosphere. It leads to formation of nc-Si with diameter about 3-5 nm. Photoluminescence (PL) at room temperature is observed in such structures, position of PL band is in range of 700-950 nm. In recent papers we offered new method that allow to control nc-Si size and spectral range of PL by forming porous SiOx film using oblique deposition of silicon monoxide. Film obtained by oblique deposition has columnar structure (diameter of columns 10-50 nm). Annealing of such film leads to formation of nc-Si in volume limited by column size, that is nc-Si of smaller size are forming. Film obtained by oblique deposition is porous (porosity up to 57%). In this work we investigated the influence of chemical treatment in ammonia and acetone vapor on PL spectra of porous nc-Si-SiOx structures. Oblique deposited films were treated by saturated vapour of acetone or ammonia before anneal. This chemical treatment leads to the considerable changes in PL spectra effecting as on the band shape as on intensity. A new intensive PL band (with peak position near 590 nm) appears after annealing in samples treated in ammonia, and with peak near 600-610 nm in samples treated in acetone vapor. IR transmission spectra of treated and annealed films demonstrates appearance of silicon nitrides bands (for samples treated in ammonia) and bands connected with carbonization (for samples treated in acetone). It is assumed that the changes in PL spectra is caused by modification of nc-Si-SiOx interface with N or C atoms. Replacement of oxygen in Si-SiOx interface by N or C modifies electronic structure of excitons involved in light emitting process. Shortwave band (590-610 nm) that appears after chemical treatment is blueshifted for 0,6 eV in comparison with nontreated samples. The value of 0,6 eV is in good agreement with other works where oxide matrix with embedded nc-Si was replaced by nitride or carbon matrix. Thus chemical treatments in ammonia and acetone vapor are efficient methods that allow to increase PL intensity of the silicon nanocrystals embedded in the oxide matrix and vary PL peak position in wide range from 560 to 950 nm.