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Amorphous hydrogenated carbon films with different nitrogen content (a-C:H:N) were deposited (thickness 2.65–3.01μm) by plasma-activated chemical vapour deposition of acetylene+nitrogen (0–62vol%) onto glass/Si substrates at a deposition temperature of ∼523K and a negative bias voltage ∼500V. The fundamental optical absorption edge was studied by optical transmittance measurements. With increasing...
Structural investigations of Si films prepared by laser-assisted deposition indicate that the strong visible photoluminescence can be related to the presence of crystalline cubic Si (c-Si) inclusions in an amorphous media with smooth surface morphology. The PL characteristics are determined by the specific short-range arrangement of Si atoms in the amorphous media and by the size and the density of...
In the present paper, we investigate the effect of the non-abrupt interfaces on the electronic and optical properties of short-period AlAs/GaAs superlattices with embedded GaAs quantum wells. The lateral disorder and the component interdiffusion at the interfaces are averaged over the layer planes and are effectively represented by a diffusion concentration profile in the growth direction. The diffusion...
Photoluminescence (PL) spectra of GaAs quantum wells embedded in short-period AlAs/GaAs superlattices have been measured at 2K and at room temperature. Two approaches have been applied in order to investigate the mechanisms of radiative recombination in these structures. In the first one, we studied the excitation density dependence of the PL intensity. In the second approach a line-shape analysis...
Molecular beam epitaxy-grown InGaAs/GaAs multilayer structures were used to characterise for their indium composition, quantum well widths and energy levels in quantum wells employing low-temperature photoluminescence spectroscopy. The effect of surface segregation and thermal desorption of indium atoms in these structures which changes the intended square well and barrier profiles is demonstrated...
Optical properties of bulk Cd 1-x Mg x Se mixed crystals, grown from a CdSe, Mg, and Se melt by the Bridgman method, are presented. The alloys have a wurtzite type structure in the investigated range of composition, i.e. for 0=<x=<0.4. Measurements of the complex pseudo-dielectric function, < (ω)>=< 1 (ω)>+i 2 (ω)>, were performed at...
Cd 1-x Mg x Se crystals for 0<x<0.55 have been grown by the high-pressure Bridgman method. Bulk chemical analysis of crystals was performed using an emission spectrometer. Auger electron spectroscopy (AES) with simultaneous argon ion sputtering has been used to monitor the changes of concentrations of particular elements in the sub-surface region of the samples. Comparison...
Rigorous computer simulations of the dependence of the band-to-band photoluminescence quantum efficiency (Y PL ) were performed for n-type InP surfaces in a wide range of excitation light intensity, Φ (from 10 18 to 10 25 cm -2 s -1 ). A strong influence of the density of surface states (N SS ) and their capture cross sections...
Effects of helium ion irradiation on photoluminescence spectrum of porous silicon were investigated. Photoluminescence spectra were measured for silicon prepared by only anodization (porous silicon), by only helium ion irradiation, and by helium ion irradiation before or after anodization. The porous silicon prepared only by anodization showed a photoluminescence spectrum with a peak intensity at...
a-Si 1-x C x :H thin films doped with different concentrations of Tb have been deposited by magnetron co-sputtering. The carbon content in the films is varied in order to change the optical gap. RBS analysis shows that Tb is homogeneously distributed in the bulk. Optical absorption spectra in the visible are studied and changes in the optical gap and the defect absorption...
Results on room-temperature photoluminescence (PL) are reported for ultra-high molecular weight polyethylene (UHMWPE) and 8vol% Bi 12 SiO 20 filled UHMWPE implanted by 30keV carbon ions at different doses from D C +=5.10 14 to 1.10 17 C + cm -2 both before and after a subsequent gamma irradiation treatment. The possible...
Polycrystalline Cd 0.96 Zn 0.04 Te thin films are deposited onto glass substrates (Corning 7059) kept at room temperature by vacuum evaporation. The films exhibit zinc blende structure with predominant (111) orientation. The rms roughness of the films evaluated by atomic force microscope is 3.7nm. The band gap energy of the films measured by optical transmittance...
The results of the research into the influence of argon ion irradiation at 3keV on the composition and structure of porous silicon are presented. At a certain angle of incidence of the particles relative to the surface of the monocrystallites, an undulating λ~60nm nanorelief is formed, while the crystallite sizes and structure remain unchanged. The IR-spectroscopy data show that SiH groups are mainly...
The photoluminescent (PL) properties of two novel types of conjugated polymer layers were studied. The layers were deposited by a centrifugation method using a special vacuum setup. The PL spectra of the layers were detected at different wavelengths of excitation light. The results suggest that the investigated conjugated polymers can be used as electroluminescent display structures with different...
Er-doped SiO 2 layers containing silicon nanoclusters were obtained by dual ion implantation and subsequent annealing. All the double beam implantations of Er and Si ion were sequentially and simultaneously performed at 900 and 200keV to doses of 1.2×10 15 and 8×10 16 /cm 2 , respectively. After these implantations, the samples were annealed at a temperature range of...
Photoluminescence (PL) properties of 500nm thick SiO 2 films on Si substrate subjected to combined Ge–Si implantations have been studied: Sequentially 400keVGe + and 200keVSi + ions were implanted into SiO 2 to concentrations of 3% and 1–10%, respectively. As calculated using the SRIM 2000 code, under these conditions depth profiles of implanted species should be contained...
The photoluminescence (PL) of Si + -implanted SiO 2 thermal films and (11¯02) sapphire substrates was studied for wide ranges of ion doses and annealing temperatures (T ann ). The regularities of the PL at 780nm from Si nanocrystals (NC) embedded in SiO 2 matrix for Tann=1000–1200°C are described based on a model that takes into account coalescence of nearest NCs and...
SiC films were prepared by the RF-magnetron sputtering technique on P-Si substrates with the target of single crystalline SiC. The as-deposited films were annealed in the temperature range of 700–1000°C under nitrogen ambient. The thin films have been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Auger electron...
Photoluminescent porous layers were formed on highly resistive p-type silicon by a metal-assisted chemical etching method using K 2 Cr 2 O 7 as an oxidizing agent. A thin layer of Ag is deposited on the (100) Si surface prior to immersion in a solution of HF and K 2 Cr 2 O 7 . The morphology of the porous silicon (PS) layer formed by this method as a...
Fe is deposited on a single crystal bulk Si (100) and separated by implanted oxygen (SIMOX) substrate by the use of ion beam sputter deposition (IBSD) method to form β-FeSi 2 film. Photoluminescence (PL) is measured for these films, after the films on Si substrate are thermally annealed at 1153K for 24h. The PL intensity at around 0.83eV dramatically increased. Such feature has not been seen...
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