Strukturna svojstva a-Si1−xCx:H SAXS-om i IR spektroskopijom

The a-Si1-xCx:H thin films, with carbon concentrations up to x = 0.3 deposited by means of a DC magnetron sputtering source, using benzene vapour as the origin of carbon atoms, were analysed by small-angle X-ray scattering (SAXS) and IR spectroscopy. The incorporation of carbon atoms in a-Si:H results in the appearance of IR absorption related to the Si-C and C-H bonds and a slight decrease of absorption related to Si-H bonds. By increasing the carbon concentration, stretching frequency of Si-H bonds increases. This frequency, which is related to the described changes, is considered to be the consequence of an increasing void volume ratio and/or void volume per each Si-H oscillator. The SAXS data of pure a-Si:H indicate ``particles" with the giro radius RG = 1.27 nm, which increases with the carbon content up to RG = 2.05 nm. These ``particles" are attributed to the clusters of small voids with dimensions up to several silicon vacancies.Primijenili smo raspršenje rendgenskog zračenja pod malim kutom (SAXS) i infracrvenu spektrometriju (IR) za analize tankih slojeva a-Si1−xCx:H, napravljenih DC magnetronskim izvorom čestica u prisustvu benzenskih para, za više koncentracija ugljika do x = 0.3. Ugradivanje ugljikovih atoma u a-Si:H ima za posljedicu pojavljivanje IR apsorpcije zbog Si-C i C-H vezanja i slabo smanjenje apsorpcije u području koje odgovara Si-H vezanju. S povećanjem koncentracije ugljika, povećava se frekvencija istezanja Si-H vezanja. Ta frekvencija, koja je u svezi s opisanim promjenama, smatra se posljedicom povećanog udjela praznina i/ili volumena praznine po Si-H oscilatoru. Podaci SAXS za čisti a-Si:H ukazuju na “čestice” sa žiro polumjerom RG = 1.27 nm koji se poveća za veće sadržaje ugljika do RG = 2.05 nm. Te se “čestice” pridjeljuju nakupinama malih praznina. Njihov je volumen reda veličine nekoliko jednoatomskih praznina u siliciju

Silicon surface irradiated by nitrogen laser radiation

Monocrystalline silicon target was irradiated with a nitrogen laser beam (alfa = 337 nm, maximum energy density 1.1 J/cm^2, pulse duration 6 ns and repetition rate 0.2 Hz). The plasma formed at the silicon surface was observed spetroscopically in air (n_e = 3×10^18 cm^-3, T_e = 18 500 K) and in vacuum (n_e = 6.5×10^17 cm^-3, T_e = 16 000 K). The irradiated surface in vacuum was studied by a metallographic microscope. Droplets were created at crater edges. Their formation is explained by the hydrodynamical sputtering model

Površina silicija ozračena dušikovim laserskim zračenjem

Monocrystalline silicon target was irradiated with a nitrogen laser beam (λ = 337 nm, maximum energy density 1.1 J/cm2, pulse duration 6 ns and repetition rate 0.2 Hz). The plasma formed at the silicon surface was observed spetroscopically in air (ne = 3×1018 cm-3, Te = 18 500 K) and in vacuum (ne = 6.5×1017 cm-3, Te = 16 000 K). The irradiated surface in vacuum was studied by a metallographic microscope. Droplets were created at crater edges. Their formation is explained by the hydrodynamical sputtering model.Monokristalni silicij se ozračivao snopom iz dušik ovog lasera (λ = 337 nm, maksimalna snaga 1.1 J/cm2 , trajanje pulsa 6 ns i frekvencija 0.2 Hz). Plazma nastala na površini silicija se promatrala spektroskopski u zraku (ne = 3 = 1018 cm 3 , Te 18500 K) i u vakuumu (ne = 6 ¬ 5 = 1017 cm 3 , Te = 16000 K). Površina ozračena u vakuumu se proučavala pomoću metalografskog mikroskopa. Opazile su se kapljice oko ruba udubine na siliciju. Nastajanje kapljica se tumači hidrodinamičkim modelom