Nanocrystalline CdSe Thin Films of Different Morphologies in Thermal Evaporation Process

2008 ◽  
Vol 8 (12) ◽  
pp. 6474-6480 ◽  
Author(s):  
U. Pal ◽  
M. Herrera Zaldivar ◽  
R. Sathyamoorthy ◽  
V. Manjuladevi ◽  
P. Sudhagar ◽  
...  
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Quantum Confinement Effect ◽  
Band Gap Energy ◽  
Morphological Variations ◽  
Glass Substrates ◽  
Interface Strain ◽  
Average Size ◽  
Film Interface ◽  
Nanocrystalline Thin Films

Cadmium selenide nanocrystalline thin films of quasi-spherical morphology are prepared by evaporating CdSe nanopowders on glass substrates. Slightly oval shaped CdSe particles of about 165 nm average size (in 2-D) could be assembled over glass substrates by controlling the film thickness. Morphologies like assembly of particles, interconnected particles with mosaic-like structures and thin films of smooth surfaces could be prepared simply by controlling film thickness. A mechanism for such morphological variations is proposed. Observed variation of band gap energy in the films is explained in terms of quantum confinement effect and substrate-film interface strain.

Sol-gel growth of Ni doped CdS on glass substrates: effect of spin coating speed and dopant concentration

2020 ◽  
Vol 10 ◽  
Author(s):  
Atefeh Nazari Setayesh ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spin Coating ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Rotation Speed ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Glass Substrates

Background: In this work, CdS thin films were synthesized by sol-gel method (spin coating technique) on glass substrates to investigate the optical behavior of the film. Methods: Different substrate spin coating speeds of 2400, 3000, 3600 rpm and different Ni dopant concentrations of 0 wt.%, 2.5 wt.%, 5 wt.%) were investigated. The optical properties of thin films such as refraction index, extinction coefficient, dielectric constant and optical band gap energy of the layers were discussed using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. Results: It can be deduced that substrate rotation speed and dopant concentration has influenced the optical properties of thin films. By decreasing rotation speed of the substrate which results in films with more thicknesses, more optical interferences were appeared in the results. Conclusion: The samples doped with Ni comparing to pure ones have had more optical band gap energy.

Fabrication and Photoelectrochemical Characterization of Fe, Co, Ni and Cu-Doped TiO2 Thin Films

2013 ◽  
Vol 764 ◽  
pp. 266-283 ◽  
Author(s):  
Ibram Ganesh ◽  
Rekha Dom ◽  
P.H. Borse ◽  
Ibram Annapoorna ◽  
G. Padmanabham ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Metal Ions ◽  
Band Gap ◽  
Metal Ion ◽  
Band Gap Energy ◽  
Chemical Compositions ◽  
Gap Energy ◽  
Glass Substrates ◽  
Photoelectrochemical Characterization

Different amounts of Fe, Co, Ni and Cu-doped TiO2 thin films were prepared on fluorine doped tin oxide (FTO) coated soda-lime glass substrates by following a conventional sol-gel dip-coating technique followed by heat treatment at 550 and 600°C for 30 min. These thin films were characterized for photo-current, chronoamperometry and band-gap energy values. The chemical compositions of metals-doped TiO2 thin films on FTO glass substrates were confirmed by XPS spectroscopic study. The metal-ions doped TiO2 thin films had a thickness of <200 nm="" optical="" transparency="" of="">80%, band-gap energy of >3.6 eV, and a direct band-to-band energy transition. The photoelectrochemical (PEC) studies revealed that all the metal-ions doped TiO2 thin films exhibit n-type semi-conducting behavior with a quite stable chronoamperometry and photo-currents that increase with the increase of applied voltage but decrease with the dopant metal-ion concentration in the thin film. Furthermore, these thin films exhibited flat-band potentials amenable to water oxidation reaction in a PEC cell. The 0.5 wt.% Cu-doped TiO2 thin film electrode exhibited an highest incident photon-to-current conversion efficiency (IPCE) of about 21%.

Dependence of Film Thickness on Properties of Al Doped ZnO Thin Films

2011 ◽  
Vol 194-196 ◽  
pp. 2305-2311
Author(s):  
Ying Ge Yang ◽  
Dong Mei Zeng ◽  
Hai Zhou ◽  
Wen Ran Feng ◽  
Shan Lu ◽  
...  
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Electrical Parameter ◽  
Substrate Surface ◽  
Rf Magnetron Sputtering ◽  
Thickness Effect ◽  
Visible Range ◽  
Glass Substrates ◽  
Doped Zno

In this study high quality of Al doped ZnO (ZAO) thin films were prepared by RF magnetron sputtering on glass substrates at room temperature in order to study the thickness effect upon their structure, electrical and optical properties. XRD results show that the films are polycrystalline and with strongly preferred (002) orientation perpendicular to substrate surface whatever the thickness is. The crystallite size was calculated by Williamson-Hall method, while it increases as the film thickness increased. The lattice stress is mainly caused by the growth process. Hall measurements revealed electrical parameter very dependent upon thickness when the thickness of ZAO film is lower than 700 nm. The resistivity decreased and the carrier concentration and Hall mobility increases as the film thickness increased. When film thickness becomes larger, only a little change in the above properties was observed. All the films have high transmittance above 90% in visible range. Red shift of the absorption edge was observed as thickness increased. The optical energy bandgap decreased from 3.41eV to 3.30 eV with the increase of film thickness.

Preparation and characterization of V2O5 doped SiO2-TiO2 thin films

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Marek Nocuń ◽  
Sławomir Kwaśny
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Dip Coating ◽  
Band Gap Energy ◽  
Tio2 Thin Films ◽  
Glass Substrates ◽  
Gel Technique

AbstractIn our investigation, V doped SiO2/TiO2 thin films were prepared on glass substrates by dip coating sol-gel technique. Chemical composition of the samples was studied by X-ray photoelectron spectroscopy (XPS). Transmittance of the samples was characterized using UV-VIS spectrophotometry. Subsequently band-gap energy (Eg) was estimated for these films. Powders obtained from sols were characterized by FTIR spectroscopy. It was found that vanadium decreases optical band gap of SSiO2/TiO2 films.

INVESTIGATING ANNEALING EFFECT ON OPTICAL PROPERTIES OF Cd0.8Zn0.2S THIN FILMS

2014 ◽  
Vol 21 (05) ◽  
pp. 1450073 ◽  
Author(s):  
SOMAYEH AZIZI ◽  
HAMID REZAGHOLIPOUR DIZAJI ◽  
MOHAMMAD HOSSEIN EHSANI ◽  
SEYED FEYZOLAH GHAVAMI MIRMAHALLE
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Hexagonal Wurtzite Structure ◽  
Band Gap Energy ◽  
Annealing Effect ◽  
Thin Layers ◽  
Optical Parameters ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Glass Substrates

Cd 0.8 Zn 0.2 S thin films deposited on glass substrates by thermal evaporation method were annealed at different temperatures for the first time in order to investigate annealing effect on optical properties. The compositional, structural of nanoparticles precursor synthesized using microwave irradiation method and optical properties of the films were studied using energy dispersive X-ray (EDX), X-ray diffraction, transmission electron microscopy (TEM), and UV-visible spectrophotometer techniques. The annealed films were found to have hexagonal Wurtzite structure with strong preferential orientation along the (002) diffraction peak. Important optical parameters such as extinction coefficient and refractive index revealed the effect of heat treatment on the deposited thin layers. A reduction in the band gap energy from 2.41 eV to 2.29 eV was observed for the annealed samples.

Properties of CdS Thin Films Grown by Chemical Bath Deposition as a Function of Bath Temperature

2009 ◽  
Vol 609 ◽  
pp. 243-247 ◽  
Author(s):  
H. Moualkia ◽  
S. Hariech ◽  
M.S. Aida
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Chemical Bath Deposition ◽  
Bath Temperature ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Cds Thin Films ◽  
Direct Band

The present work deals with the preparation and characterization of cadmium sulfur (CdS) thin films. These films are prepared by chemical bath deposition on the well cleaned glass substrates. The thickness of the samples was measured by using profilometer DEKTAK, structural and optical properties were studied by X-ray diffraction analysis, and UV-visible spectrophotometry. The optical properties of the films have been investigated as a function of temperature. The band gap energy and Urbach energy were also investigated as a function of temperature. From the transmittance data analysis the direct band gap ranges from 2.21 eV to 2.34 eV. A dependence of band gap on temperature has been observed and the possible raisons are discussed. Transmission spectra indicates a high transmission coefficient (75 %). Structural analysis revealed that the films showed cubic structure, and the crystallite size decreased at a higher deposition temperature.

scholarly journals Optical Properties of Undoped and Indium-doped Tin Oxide Thin Films

2011 ◽  
Vol 35 (1) ◽  
pp. 99-111 ◽  
Author(s):  
Fatema Rezwana Chowdhury ◽  
Shamima Choudhury ◽  
Firoz Hasan ◽  
Tahmina Begum
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Tin Oxide ◽  
Optical Transmittance ◽  
Band Gap Energy ◽  
Visible Range ◽  
Absorption Region ◽  
Gap Energy ◽  
Glass Substrates ◽  
In Doping

Thin films of Tin Oxide (SnO2), having thickness of 200 nm, were formed on to glass substrates by thermal evaporation of high-purity SnO2 powder in vacuum at various substrate temperatures (TS), ranging between 25 and 200°C. SnO2 films with varying thickness were also prepared for a fixed TS = 100°C. Further, doping of SnO2 films with Indium (In) was accomplished through solid state diffusion process by successive deposition of SnO2 and In films and subsequent annealing at 200°C for 10 minutes. Both undoped and doped films were characterized optically by UV-VIS-NIR spectrophotometry in the photon wavelength ranging from 300 to 2500 nm. In the visible photon wavelength range, the average optical transmittance (T%) of the films with varying TS was found to be 85%. The maximum value of T % was found to be 89 % around the wavelength of 700nm. The variation of absorption coefficient with photon energy in the fundamental absorption region is the steepest for TS = 100°C. The sub-band gap (SBG) absorption is also minimum for this Ts. A fluctuating behavior of the band gap energy (Eg) with Ts is observed attaining the highest value of 3.59 eV for Ts = 100°C. The band gap energy increases with thickness but T% in the visible range decreases. The T% in the visible range varies inversely with indium doping, being highest for undoped films. The Eg increases upto 2 wt% In doping and gradually decreases for enhanced doping. It seems reasonable to conclude that In doping does not bring favorable optical characteristics. Undoped SnO2 films having thickness of 200 nm and formed at substrate temperature of 100°C yield essential acceptable properties for photovoltaic applications.DOI: http://dx.doi.org/10.3329/jbas.v35i1.7975Journal of Bangladesh Academy of Sciences, Vol.35, No.1, 99-111, 2011

scholarly journals Effects of Sulfurization Temperature on Properties of CZTS Films by Vacuum Evaporation and Sulfurization Method

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jie Zhang ◽  
Bo Long ◽  
Shuying Cheng ◽  
Weibo Zhang
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Band Gap ◽  
Crystallite Size ◽  
Low Cost ◽  
Band Gap Energy ◽  
Vacuum Evaporation ◽  
Glass Substrates ◽  
Sulfurization Temperature ◽  
Czts Thin Films

Copper zinc tin sulfur (CZTS) thin films have been extensively studied in recent years for their advantages of low cost, high absorption coefficient (≥104 cm−1), appropriate band gap (~1.5 eV), and nontoxicity. CZTS thin films are promising materials of solar cells like copper indium gallium selenide (CIGS). In this work, CZTS thin films were prepared on glass substrates by vacuum evaporation and sulfurization method. Sn/Cu/ZnS (CZT) precursors were deposited by thermal evaporation and then sulfurized in N2+ H2S atmosphere at temperatures of 360–560°C to produce polycrystalline CZTS thin films. It is found that there are some impurity phases in the thin films with the sulfurization temperature less than 500°C, and the crystallite size of CZTS is quite small. With the further increase of the sulfurization temperature, the obtained thin films exhibit preferred (112) orientation with larger crystallite size and higher density. When the sulfurization temperature is 500°C, the band gap energy, resistivity, carrier concentration, and mobility of the CZTS thin films are 1.49 eV, 9.37 Ω · cm,1.714×1017 cm−3, and 3.89 cm2/(V · s), respectively. Therefore, the prepared CZTS thin films are suitable for absorbers of solar cells.

scholarly journals Electrical characterization of aluminum (Al) thin films measured by using four- point probe method

2013 ◽  
Vol 8 (2) ◽  
pp. 31-36 ◽  
Author(s):  
GP Panta ◽  
DP Subedi
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Film Thickness ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Electrical Characterization ◽  
Probe Method ◽  
Glass Substrates ◽  
Engineering And Technology

This paper reports the results of electrical characterization of aluminum thin films. Uniform Al thin films were deposited by physical vapor deposition (PVD) technique on glass substrates. The electrical resistivity of the films as a function of film thickness was studied. These parameters have been measured by four-point probe method. The electrical resistivity was obtained by the measurement of current (in mA) and voltage in (mV) through the probe. The results showed that resistivity of the film decreases linearly with the film thickness in the range of the thickness studied in this work. Kathmandu University Journal of Science, Engineering and Technology Vol. 8, No. II, December, 2012, 31-36 DOI: http://dx.doi.org/10.3126/kuset.v8i2.7322

Structural Properties of Ag-Based Chalcopyrite Compound Thin Films for Solar Cells

2005 ◽  
Vol 865 ◽  
Author(s):  
Hiroki Ishizaki ◽  
Keiichiro Yamada ◽  
Ryouta Arai ◽  
Yasuyuki Kuromiya ◽  
Yukari Masatsugu ◽  
...  
Keyword(s):  
Thin Films ◽  
Rietveld Analysis ◽  
Atomic Ratio ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Glass Substrates ◽  
Crystallographic Property ◽  
Chalcopyrite Compound

AbstractAgGa5Se8 and Ag(In1-xGax)Se2 thin films with different Ag/Ga atomic ratios have been deposited on the corning 1737 glass substrates by molecular beam epitaxy (MBE) system. This crystallographic property of AgGa5Se8 thin films has been investigated by x-ray diffraction and rietveld analysis. These films had the tetragonal structure with the space group of P-42m, regardless of Ag/Ga atomic ratio. The lattice parameters and the optical band gap energy decreased with an increase in the Ag/Ga atomic ratio. Thus, the structural and optical properties of these AgGa5Se8 thin films were controlled by the Ag/Ga atomic ratio.

Sign in / Sign up

Export Citation Format

Share Document