<p>U ovom radu prikazani su rezultati ispitivanja termičkih, mehaničkih, električnih i optičkih karakteristika kvazibinarnih halkogenida iz sistema Bi-As2S3. Na osnovu termičkih merenja analizirana je kinetika kristalizacionih i predkristalizacionih procesa i utvrđen je mehanizam dekompozicije za različite sastave dobijenih stakala. Primenom impedansne spektroskopije kvantitativno su ocenjeni doprinosi relaksacionih procesa na pojedinim temperaturama u ukupnoj polaraziciji za stakla sa 5 i 7 at.% Bi. Na osnovu merenja Raman spektroskopije identifikovane su nastale strukturne jedinice i konstatovana pojava nanofazne separacije u staklima sa 1.5 i 3 at.% Bi. Mehanička merenja ispitivanih halkogenida različitog sastava ukazala su na povećanje Vickers-ove tvrdoće sa povećanjem udela primesnih atoma. Na osnovu procenjene vrednosti modula elastičnosti ustanovljeno je da uzorak sa 5 at.% Bi odlikuje najgu&scaron;će atomsko pakovanje. Merenja električnih karakteristika u jednosmernom režimu (DC) pokazala su da je udeo lokalizovanih stanja u ukupnom mehanizmu provođenja značajan samo za manje koncentracije primesnih atoma, a da za veće koncentracije dominantan faktor postaju preskoci između delokalizovanih stanja. Skok u provodljivosti za nekoliko redova veličine kod sastava sa složenijom strukturom protumačen je kao posledica fazne separacije. Rezultati&nbsp; ACmerenja dobijeni za sastav sa 5 at.% Bi ukazali su da je u mernom frekventnom intervalu i dalje dominantan mehanizam termičke aktivacije nosilaca naelektrisanja. Kod sastava sa maksimalnim sadržajem Bi uočena je promena provodljivosti u funkciji frekvencije na svim temperaturama, a dobijeni rezultati su u skladu sa postavkama modela korelisanih preskoka barijere (CHB model).</p> / <p>This paper presents the results of investigation ofthermal, mechanical, electrical and optical propertiesof quasibinar chalcogenides from the system Bi-As2S3.&nbsp;Kinetics analysis of softening and crystallizationprocesses was done on the basis of thermalmeasurements, as well the analysis of decompositionmechanism for different compositions of obtainedglasses. The application of impedance spectroscopy enabled quantitative description of relaxation process contributions at selected temperatures in the overallpolarization for the samples with 5 and 7 at.% Bi.&nbsp;Based on measurements of Raman spectroscopy identification of structural units in the investigated chalcogenides was made, as well as the appearance of&nbsp;nano-scale phase separation in the glasses with 1.5 and 3 at.% Bi. Mechanical measurements pointed to the increase of the Vickers hardness with increase of&nbsp;doping atoms content. &nbsp;Based on the estimated value of the modulus of elasticity it was found that the sample &nbsp;with 5 at.% Bi is characterized by the densest atomic&nbsp;arrangement. Measurements of the electrical properties in dc regime (DC) pointed out that the share of localized states in the whole mechanism of conduction&nbsp;is significant only for the smaller concentrations of doping atoms. For the samples with higher concentrations dominant &nbsp;factor in conductivity are transitions between delocalized states. The jump in conductivity by few orders of magnitude, noticed for&nbsp;the compound with heterogeneous structure was interpreted as a consequence of micro-scale phase&nbsp; separation. Results of&nbsp; ACmeasurements for the&nbsp; composition with 5 at.% Bi showed that the mechanism of thermal activation of charge carriers is&nbsp;still dominant in the measured frequency range. For&nbsp;&nbsp; the composition with the maximum content of Bi changes in conductivity versus frequency were observed at all temperatures, and the results were interpreted in accordance with the model of correlated hopping over the barrier (CHB).</p>

<p>Predmet istraživanja ove doktorske disertacije su bila halkogenidna stakla iz sistema Ag_x(As₄₀S₃₀Se₃₀)_100&ndash;x (x = 0, 0.5, 1, 2, 3, 4, 5, 10, 12, 13, 15 at. % Ag) &ndash; 3D forma i tanki filmovi preparirani iz prethodno sintetisanih stakala (x &le; 5 at. % Ag) &ndash; 2D forma.<br />Utvrđena je oblasti amorfnosti u faznom dijagramu po odabranom preseku.&nbsp; Ispitivan je uticaj procentualnog udela srebra&nbsp; na&nbsp; fizičke&nbsp; karakteristike sintetisanih stakala i prepariranih tankih filmova koje su&nbsp; od&nbsp; značaja&nbsp; za&nbsp; primenu&nbsp; ovakvih&nbsp; materijala.<br />Izvr&scaron;ena je karakterizacija električnih,&nbsp; optičkih, strukturnih&nbsp; i&nbsp; termičkih&nbsp; osobina&nbsp; na&nbsp; osnovu&nbsp; kojih&nbsp; su izvedeni&nbsp; zaključci&nbsp; o&nbsp; uticaju&nbsp; i&nbsp; modifikaciji&nbsp; strukture As₄₀S₃₀Se₃₀halkogenidne matrice usled inkorporacije atoma srebra. Strukturna analiza ispitivanih sastava je potvrdila homogenost uzoraka sa manjom koncentracijom srebra (x &le; 5 at. %&nbsp; Ag), dok je&nbsp; kod uzoraka sa većim procentualnim udelom ovog metala (x = 10, 13, 15 at. % Ag) pokazano da postoji fazna separacija. Kod sastava sa x = 13 i 15 at. % Ag potvrđena&nbsp; je&nbsp; prisutnost kristalnih centara AgAsSe_2. Na osnovu rezultata dobijenih DSC tehnikom, pokazano je da pri zagrevanju balk uzoraka dolazi do delimične kristalizacije koja se odvija zapreminski sa dvodimenzionalnim&nbsp; i&nbsp; trodimenzionalnim rastomkristalnih centara. Optička i spektralna ispitivanja su pokazala&nbsp; da uvođenje&nbsp; Ag&nbsp; u&nbsp; matricu&nbsp; stakla As₄₀S₃₀Se₃₀&nbsp; dovodi&nbsp; do&nbsp; smanjenja&nbsp; &scaron;irine&nbsp; optički zabranjene zone i kod 3D i 2D uzoraka, kao i da svi sastavi ispoljavaju normalan oblik disperzije indeksa prelamanja. Takođe, rezultati Raman&nbsp; spektroskopije su ukazali&nbsp; na&nbsp; činjenicu&nbsp; da&nbsp; inkorporacija&nbsp; srebra&nbsp; u strukturnu&nbsp; mrežu&nbsp; ispitivanih&nbsp; stakala&nbsp; utiče&nbsp; na formiranje Ag&ndash;(S,Se)&ndash;As veza, odnosno uzrokuje formiranje novih strukturnih jedinica koje bi mogle uticati na provodljivost ovih sastava.&nbsp; Merenja električnih karakteristika 3D uzoraka izvr&scaron;ena su u jednosmernom i naizmeničnom režimu i pokazano je da&nbsp; koncentracija&nbsp; srebra&nbsp; ima&nbsp; značajan&nbsp; uticaj&nbsp; na električne&nbsp; osobine.&nbsp; Utvrđeni&nbsp; su&nbsp; različiti&nbsp; mehanizmi odgovorni za transport&nbsp; nosilaca naelektrisanja zavisno od&nbsp; koncentracije dopanta.&nbsp; Kompleksni impedansni spektri svih sastava&nbsp; su&nbsp; ukazali&nbsp; na prisustvo temperaturske zavisnosti procesa relaksacije, na ne idealan Debye&ndash;vski tip relaksacije, kao i negativni temperaturski koeficijent otpornosti koji je karakterističan za poluprovodnike.</p> / <p>The subject of this dissertation are chalcogenide&nbsp; glasses from the system Agx(As₄₀S₃₀Se₃₀)_100&ndash;x (x = 0, 0.5, 1, 2, 3, 4, 5, 10, 12, 13, 15 at. % Ag) &ndash; 3D form and thin films prepared from previously synthesised&nbsp; glasses (x &le; 5 at. % Ag) &ndash; 2D form. The amorphous&nbsp; area in the phase diagram was determined by the&nbsp; selected&nbsp;&nbsp;&nbsp; tie&ndash; line. The influence of the silver&nbsp; percentage on the physical characteristics of the&nbsp; synthesized glasses and prepared thin films was&nbsp; investigated due to the importance of such materials&nbsp; for the application. Characterization of electrical, optical, structural and thermal properties has been performed, based on which conclusions on theinfluence and structure modification of the As₄₀S₃₀Se₃₀&nbsp; chalcogenide&nbsp; matrix due to the&nbsp; incorporation of silver atoms have been derived. Structural analysis of the investigated samples confirmed the homogeneity of samples with a lower silver concentration (x&nbsp; &le;&nbsp; 5&nbsp; at.%&nbsp; Ag),&nbsp; while&nbsp; in samples with a higher percentage content of&nbsp; this metal (x = 10, 13, 15 at.% Ag) it was shown that&nbsp; there was a phase separation. The presence of crystal&nbsp; centers AgAsSe₂ was confirmed in the samples with x = 13 and 15 at. % Ag. Based on the results obtained with the DSC technique, it has been shown that by heating the samples, partial crystallization takes place voluminously, with two&ndash;dimensional and three&ndash;dimensional growth of crystalline centers.&nbsp; Opticaland spectral investigations have shown that the introduction of Ag into the glass matrix As₄₀S₃₀Se₃₀ leads to a reduction in the optical band gap in both 3D and 2D samples, and that all compositions exhibit a normal dispersion of index of&nbsp; refraction. Also, the Raman spectroscopy results pointed to the fact that the incorporation of silver into the structural network of the investigated samples influences the formation of&nbsp; Ag&ndash;(S,Se)&ndash;As structures that is, causes the formation of new structural units that could affect the conductivity of these compositions. Measurements of the electrical characteristics of the 3D samples were performed in&nbsp; DC and AC regime and it was shown that silver concentration has a significant effect on electrical properties. Different mechanisms that are responsible for the transport of charge carriers depending on dopant concentration were determined. The complex&nbsp; impedance spectra of all compositions indicated the presence of the temperature dependence of the relaxation process, the non&ndash;Debye relaxation and the negative temperature coefficient of resistance which is characteristic of the semiconductors.</p>