Wyniki wyszukiwania - BazTech

1

Deposition time and annealing effects on morphological and optical properties of ZnS thin films prepared by chemical bath deposition

Chabou N., Birouk B., Aida M. S., Raskin J. P.

Materials Science Poland

|

2020

|

Vol. 38, No. 4

508--517

EN

Nanocrystalline zinc sulfide (ZnS) thin films are prepared on glass substrates by chemical bath deposition (CBD) method using aqueous solutions of zinc chloride, thiourea ammonium hydroxide along with non-toxic complexing agent tri-sodium citrate in alkaline medium at 80 °C. The deposition time and annealing effects on the optical and morphological properties are studied. The morphological, compositional, and optical properties of the films are investigated by scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDAX) and UV-Vis spectroscopy. SEM micrographs exhibit uniform surface coverage. UV-Vis (300 nm to 800 nm) spectrophotometric measurements show transparency of the films (transmittance ranging from 69 % to 81 %), with a direct allowed energy band gap in the range of 3.87 eV to 4.03 eV. After thermal annealing at 500 °C for 120 min, the transmittance increases up to 87 %.

2

Mixed structure Zn(S,O) nanoparticles: synthesis and characterization

Dhupar Anu, Kumar Suresh, Sharma Vandana, Sharma J. K.

Materials Science Poland

|

2019

|

Vol. 37, No. 2

230--237

EN

In the present work, mixed structure Zn(S,O) nanoparticles have been synthesized using solution based chemical coprecipitation technique. Two different zinc sources (Zn(CH3COO) 2·2H2O and ZnSO4·7H2O) and one sulfur source (CSNH2NH2) have been used as primary chemical precursors for the synthesis of the nanoparticles in the presence and absence of a capping agent (EDTA). The structural, morphological, compositional and optical properties of the nanoparticles have been analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transmission infra-red (FT-IR) and UV-Visible (UV-Vis) spectroscopy. XRD revealed the formation of mixed phases of c-ZnS, h-ZnS and h-ZnO in the synthesized nanoparticles. The surface morphology was analyzed from SEM micrographs which showed noticeable changes due to the effect of EDTA. EDX analysis confirmed the presence of zinc, sulfur and oxygen in Zn(S,O) nanoparticles. FT-IR spectra identified the presence of characteristic absorption peaks of ZnS and ZnO along with other functional group elements. The optical band gap values were found to vary from 4.16 eV to 4.40 eV for Zn(S,O) nanoparticles which are higher in comparison to the band gap values of bulk ZnS and ZnO. These higher band gap values may be attributed to the mixed structure of Zn(S,O) nanoparticles.

3

Deposition time and annealing effects on morphological and optical properties of ZnS thin films prepared by chemical bath deposition

Chabou N., Birouk B., Aida M. S., Raskin J. P.

Materials Science Poland

|

2019

|

Vol. 37, No. 3

404--416

EN

Nanocrystalline zinc sulfide thin films were prepared on glass substrates by chemical bath deposition method using aqueous solutions of zinc chloride, thiourea ammonium hydroxide along with non-toxic complexing agent trisodium citrate in alkaline medium at 80 °C. The effect of deposition time and annealing on the properties of ZnS thin films was investigated by X-ray diffraction, scanning electron microscopy, optical transmittance spectroscopy and four-point probe method. The X-ray diffraction analysis showed that the samples exhibited cubic sphalerite structure with preferential orientation along 〈2 0 0〉 direction. Scanning electron microscopy micrographs revealed uniform surface coverage, UV-Vis (300 nm to 800 nm) spectrophotometric measurements showed transparency of the films (transmittance ranging from 69 % to 81 %), with a direct allowed energy band gap in the range of 3.87 eV to 4.03 eV. After thermal annealing at 500 °C for 120 min, the transmittance increased up to 87 %. Moreover, the electrical conductivity of the deposited films increased with increasing of the deposition time from 0.35 × 10−4 Ω·cm−1 to 2.7 × 10−4 Ω·cm−1.

4

Investigation of Cu(In, Ga)Se2 solar cell performance with non-cadmium buffer layer using TCAD-SILVACO

Sara B., Baya Z., Zineb B.

Materials Science Poland

|

2018

|

Vol. 36, No. 3

514--519

EN

The purpose of this work is to achieve the best efficiency of Cu(In, Ga)Se2 solar cells by replacing the CdS buffer layer with other nontoxic materials. The simulation tool used in this study is Silvaco-Atlas package based on digital resolution 2D transport equations governing the conduction mechanisms in semiconductor devices. The J-V characteristics are simulated under AM1.5G illumination. Firstly, we will report the modeling and simulation results of CdS/CIGS solar cell, in comparison with the previously reported experimental results [1]. Secondly, the photovoltaic parameters will be calculated with CdS buffer layer and without any buffer layer to understand its impact on the output parameters of solar cells. The simulation is carried out with the use of electrical and optical parameters chosen judiciously for different buffers (CdS, ZnOS and ZnSe). In comparison to simulated CdS/CIGS, the best photovoltaic parameters have been obtained with ZnOS buffer layer. The structure has almost the same open circuit voltage Voc and fill factor FF, and higher short circuit current density Jsc, which results in slightly higher conversion efficiencies.

5

Investigation of multiple degradation and rejuvenation cycles of electroluminescent thick film structures

Mroczkowski M., Cież M., Kalenik J.

Elektronika : konstrukcje, technologie, zastosowania

|

2012

|

Vol. 53, nr 1

39-40

EN

An attempt to investigate the possibility of repeated rejuvenation of degraded electroluminescent (EL| lamps was undertaken. A set of samples of EL lamps with ZnS:Cu phosphor was fabricated. First, each of these samples worked for a period of time, driven by square voltage. After this process of degradation, samples were annealed in order to rejuvenate them. Such cycles of degradation and rejuvenation were repeated twice. Several parameters of investigated structures were estimated. Measurements were performed after fabrication of test samples, after degradation and after annealing. Luminance of EL lamps driven by voltage of different value of frequency was measured. Capacitance of these samples was measured to estimate the influence of changes in insulator layer of EL lamps on changes of luminance. Also an attempt to investigate the influence of degradation and rejuvenation on emission spectrum of electroluminescent thick film structures was undertaken.

PL

W ramach badań podjęto próbę wykonania wielokrotnej regeneracji zdegradowanych struktur elektroluminescencyjnych. Do tego celu został przygotowany zestaw testowych grubowarstwowych źródeł światła. Najpierw te źródła światła zostały zdegradowane przez starzenie przy zasilaniu napięciem prostokątnym. Następnie próbki wygrzano celem ich regeneracji. Taki cykl degradacji i regeneracji został wykonany dwukrotnie. Zmierzono wybrane parametry badanych struktur. Pomiary zostały wykonane po przygotowaniu próbek, po ich degradacji i po regeneracji. Zmierzono luminancję struktur zasilanych napięciem prostokątnym o różnej częstotliwości. W celu określenia wpływu zmian w warstwie izolacyjnej na luminancję struktury, zamierzono pojemność próbek. Dodatkowo, podjęto próbę określenia wpływu degradacji i regeneracji na widmo emisyjne elektroluminescencyjnych struktur grubowarstwowych.

6

Studies of rejuvenation of electroluminescent thick film structures

Mroczkowski M., Cież M., Kalenik J.

Optica Applicata

|

2011

|

Vol. 41, nr 2

481--486

EN

A set of samples of electroluminescent (EL) lamps with ZnS phosphor was fabricated. These samples were degraded in different working conditions. Next, an attempt to rejuvenate these structures by annealing was undertaken. Several parameters of investigated structures were estimated. Then, measurements were performed after fabrication of test samples, their degradation and annealing. The luminance of the test structures as a function of applied voltage frequency was measured. Also, the spectrum of light emission before and after the degradation and rejuvenation processes was investigated.

7

Properties of films fabricated from ZnS/Mn2+ nanoparticles

Zdyb A., Cieślak K., Olchowik J. M.

Materials Science Poland

|

2008

|

Vol. 26, No. 2

389--394

EN

Nanoparticles of manganese doped zinc sulfide (ZnS/Mn2+) were obtained by wet chemical method. AFM images of the nanoparticles were analysed and their size distribution was estimated. The layer of ZnS/Mn2+ nanoparticles reveals a semiconducting character. Conductivity increases with temperature and its value is of the order of 10-9 źcm-1.