Termička stabilnost silicij–ugljik amorfnih legura nanesenih magnetronskim izvorima

Amorphous a-Si0.85C0.15:H and a-Si0.6C0.4:H alloys were deposited onto a non-heated substrate using a magnetron source. The samples were exposed to a sequential iso-chronal thermal annealing up to 1000 ° C in a vacuum chamber, and were investigated by the IR spectroscopy and X-ray diffraction measurements. The influence of the thermal treatment on structural ordering was monitored by the evolution of the intensity and shape of the spectral IR lines corresponding to the Si-H and Si-C bonds. At low temperatures, the most pronounced features were accompanied with hydrogen evolution which completes up to 400 ° C. Up to 800 ° C the Si-C absorption lines have gradually changed their shape, peak position and intensity. At 900 ° C, the abrupt changes occured, denoting final transition to crystalline state.Slojevi amorfnog a−Si0.85C0.15:H i a−Si0.6C0.4:H su formirani magnetronskim izvorom, na nezagrijanoj podlozi. Nakon depozicije, uzorci su postepeno grijani u vakuumu do 1000 ◦C. Između uzastopnih grijanja vršena su mjerenja infra–crvenom spektroskopijom i difrakcijom X-zraka. Utjecaj ovakvog termalnog tretmana na strukturno uređenje uzoraka je praćeno razvojem intenziteta i oblika spektralnih linija koje odgovaraju Si−H i Si−C vezama. Na nižim temperaturama, najizrazitije promjene su vezane za desorpciju vodika, koja završava do 400 ◦C. Daljnjim grijanjem do 800 ◦C, linije postepeno mijenjaju oblik, intenzitet i frekvenciju maksimuma. Grijanje na i iznad 900 ◦C uzrokuje nagle promjene, označavajući prijelaz u kristalinično stanje

Analysis of trap spectra in LEC and epitaxial GaAs

Different methods of trap parameter measurement are analysed. Transient photoconductivity and thermally stimulated effects were used to investigate the influence of traps in LEC SI-GaAs and high resistivity epitaxial GaAs. The peculiarities of the TSC were analysed and shown to be related to the influence of crystal micro-inhomogeneities.Comment: Invited talk, 6-th Workshop on Gallium Arsenide and Related Compounds June 22-26, 1998 Praha-Pruhonice, Czech Republi

Epidemiologic characteristics of campylobacteriosis in hospitalized patients

Među 1632 bolesnika s kampilobakteriozom hospitalizirana od 1994.–2002. godine, nije utvrđen porast udjela kampilobakterioza u odnosu na sve druge uzročnike proljeva (p=0,333), niti u odnosu na salmoneloze (p=0,751), te je utvrđen porast bolesnika s C. jejuni (71,7%) u odnosu na one s C. coli (28,3%) infekcijom (p<0,001). Najviše je bolesnika u dobnoj skupini mlađih od tri godine (38,5 %), zatim u skupini 18–29 g. (9,9 %). Mu{karci prevladavaju u svim dobnim skupinama, osim u najstarijoj (≥60 g.) (p<0,001). Značajno najveći broj bolesnika je hospitaliziran u toplijim mjesecima godine; 14,3% bolesnika s C. jejuni tijekom lipnja, a po 11,5 % bolesnika s C. coli u lipnju i kolovozu (p<0,001). U skupinama seoskog, prigradskog i gradskog stanovništva je omjer bolesnika s C. jejuni i C. coli infekcijom podjednak (p=0,289). Bolest se u 83,9% bolesnika javila sporadično, a u 13,1% bolesnika nakon putovanja. Pohađanje kolektiva se pokazalo značajnim u odnosu na epidemijski oblik pojavnosti bolesti (p<0,001).Among 1632 patients with campylobacteriosis hospitalized in the period from 1994–2002, we did not record an increase in the ratio of campylobacteriosis compared to all other causative agents of diarrhoeal diseases (p=0.333), nor in comparison to salmonelloses (p=0.751), but a significant increase in the number of C. jejuni (71.7%) compared to C. coli infections (28.3 %) was noticed (p<0.001). The majority of patients belonged to age group of three years and younger (38.5 %), and to 18 –29 years group (9.9 %), respectively. Males predominated in all age groups, except in the oldest one (≥60 years) (p<0.001). Significantly highest number of patients was hospitalized during warm months of the year; 14.3% patients with C. jejuni infection during June, and 11.5 % of patients with C. coli infection in both June and August (p<0.001). In the groups of rural and urban population, the difference in the ratio between C. jejuni and C. coli infections was not recorded (p=0.289). The disease appeared in 83.9% of patients sporadically, and in 13.1% after travelling. Community setting was a significant factor in epidemic pattern of the disease (p<0.001)

Clinical characteristic of campylobacteriosis in hospitalised patients

Bolest izazavana gram-negativnim bakterijama iz roda Campylobacter u ljudi najčešće prolazi kao akutna proljevna bolest u trajanju do tjedan dana. Komplikacije bolesti su rijetke, a najznačajnije su među njima sepsa, bakterijemija s vancrijevnim žarištima zaraze, septički pobačaj, te imunološki uvjetovan Guillain-Barréov sindrom. Među 1632 bolesnika s kampilobakteriozom hospitalizirana od 1994.–2002. godine analizom pojedinih kliničkih parametara logističkom regresijom uočeno je značajno duže trajanje proljeva u bolesnika zaraženih s C. jejuni (p = 0,014, OR 1,06, 95 % CI 1,01–1,11). Komplikacije bolesti su zabilježene u 4,6 % bolesnika, a smrtni ishod ili naknadna hospitalizacija zbog Guillain-Barréovog sindroma u klinikama zagrebačkog područja nisu u njih zabilježeni. S učestalošću od 7,2 % komplikacije su bile značajno češće u dobnoj skupini mlađih od tri godine (p = 0,010). Odgovarajućim antimikrobnim lijekom je liječeno 78,7 %, neodgovarajućim antimikrobnim lijekom 6,7 %, a simptomatski 14,6 % bolesnika. Kliničke osobine u naših bolesnika s kampilobakteriozom ne odudaraju znatnije od onih opisanih u populacijama razvijenih zemalja. Kao osobitost bilježi se česta primjena antimikrobnog liječenja, a azitromicin, kojeg je dobijalo 46,4 % bolesnika liječenih odgovarajućim antimikrobnim lijekom, je najčešće primjenjivani lijek.Diseases caused by gram-negative bacteria from genus Campylobacter in humans are most often presented as an acute diarrhoeal illness, which lasts up to seven days. Complications are rare, and among them the most important are: sepsis, bacteremia with extraintestinal sites of infection, septic abortion, and immunologically triggered Guillain-Barré syndrome. Among 1632 hospitally treated patients in the period from 1994–2002, the analysis of a particular clinical parameters using logistic regression showed significantly longer duration of diarrhoea among patients with C. jejuni infection (p = 0.014, OR 1.06, 95 % CI 1.01–1.11). Disease complications were observed in 4.6 % patients, and no fatalities or hospitalisations of observed patients due to Guillain-Barré syndrome in any of the hospitals from Zagreb region were recorded. Complications were significantly more frequent (7.2 %) in the age group younger than three years (p = 0.010). Adequate antimicrobial treatment received 78.7 % of patients, unadequate antimicrobial treatment 6.7 %, and 14.6 % of patients were treated symptomaticaly. Clinical characteristics in our patients with campylobacteriosis do not differ significantly from those described in populations of developed countries. As a peculiarity, a common use of antimicrobial therapy is recorded, and azithromycin, used in 46.4 % of patients treated with adequate antimicrobial treatment, was the most frequently used drug

Damage Assessment in Low Doses 30Si+\text{}^{30}Si^{+}-Implanted GaAs

Ion implantation is a widely used technique in device technology, and becoming even more important as the size of devices decreases. The studies of damage and introduced defects have been extensive and, although the overall development and annealing of the implantation damage is relatively well understood, many details remain unclear. Especially, not enough attention has been paid to the effects of very low doses, which are particularly important in controlling the threshold voltage of transistors in the fabrication of GaAs integrated circuits. The reason might be that the induced changes were very often below the detectivity limits of standard methods. In this work, we present the disorder analysis, conducted on GaAs implanted with low ion doses. Czochralski grown, undoped, (100) oriented GaAs samples were implanted with 100 keV $\text{}^{30}Si^{+}$ ions, doses ranging from 3×$10^{11}//cm^{2}$-3×$10^{13}//cm^{2}$, at 21°C. The damage assessment was done by applying Raman scattering and Rutherford backscattering ion channeling (RBS), linked by the inter-cascade distance model and the results were then compared with the results of photoacoustic displacement technique. We have shown that Raman scattering is very sensitive method even if applied on samples implanted with very low doses. Furthermore, the equivalency between the Raman scattering and Rutherford backscattering damage assessment, previously established for high doses via the inter-cascade distance model, proved equally valid also for very low implantation doses, where implanted ions create disordered cascades that are far apart, and most of the layer is still undamaged

Damage Assessment in Low Doses 30

Ion implantation is a widely used technique in device technology, and becoming even more important as the size of devices decreases. The studies of damage and introduced defects have been extensive and, although the overall development and annealing of the implantation damage is relatively well understood, many details remain unclear. Especially, not enough attention has been paid to the effects of very low doses, which are particularly important in controlling the threshold voltage of transistors in the fabrication of GaAs integrated circuits. The reason might be that the induced changes were very often below the detectivity limits of standard methods. In this work, we present the disorder analysis, conducted on GaAs implanted with low ion doses. Czochralski grown, undoped, (100) oriented GaAs samples were implanted with 100 keV $\text{}^{30}Si^{+}$ ions, doses ranging from 3×$10^{11}//cm^{2}$-3×$10^{13}//cm^{2}$, at 21°C. The damage assessment was done by applying Raman scattering and Rutherford backscattering ion channeling (RBS), linked by the inter-cascade distance model and the results were then compared with the results of photoacoustic displacement technique. We have shown that Raman scattering is very sensitive method even if applied on samples implanted with very low doses. Furthermore, the equivalency between the Raman scattering and Rutherford backscattering damage assessment, previously established for high doses via the inter-cascade distance model, proved equally valid also for very low implantation doses, where implanted ions create disordered cascades that are far apart, and most of the layer is still undamaged

Structural Modifications in Amorphous Ge Produced by Ion Implantation

Raman spectroscopy was used to analyze structural modifications of monocrystalline Ge implanted with 3 × 1012 to 3 × 1016 cm-274Ge ions, at either room temperature (RT) or liquid nitrogen (LN) temperature. In all implanted samples, beyond the amorphiza

Direct ion beam synthesis of II-VI nanocrystals

Abstract We have studied the direct synthesis of nanoparticles formed by dual implantation of large and equal doses of Cd + S, Zn + Te, Cd + Te or Pb + Te ions into SiO 2 substrate. Grazing incidence small angle X-ray scattering (GI-SAXS), transmittance measurements and Raman spectroscopy were used to investigate implanted composites. The 2D GISAXS patterns suggest the synthesis of nanoparticles already during ion implantation, performed either at 300 or at 77 K, while annealing at higher T causes an increase of the fraction and the average size of synthesized nanoparticles. After high-T annealing both optical methods detected nanocrystals of compound semiconductors CdS, ZnTe or CdTe through the appearance of the respective first optical gaps, E g , in transmittance measurements and characteristic LO peaks in Raman spectra. It is proposed that at high ion doses a fraction of implanted atoms synthesize already during implantation into amorphous aggregates of compound semiconductor, which transform into crystalline nanoparticles after annealing