scholarly journals Hydrogenated Nano-Crystalline Silicon Thin Films in SiO2 Matrix for Next Generation Solar Cells Using Glow Discharged Decomposition

2018 ◽  
Vol 8 (1) ◽  
pp. 25
Author(s):  
Moniruzzaman Syed ◽  
Cameron Hynes ◽  
Brittany Anderson ◽  
Temer S Ahmadi ◽  
Boon Tong Goh ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Energy Gap ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Strong Dependence ◽  
Blue Shift ◽  
Nanocrystalline Silicon ◽  
Optical Energy Gap ◽  
Substrate Temperatures

Hydrogenated Nanocrystalline Silicon (nc-Si:H) thin films using SiH4/H2 mixture by glow discharged decomposition were investigated on c-Si and glass substrates. The effects of substrate temperature on the Structural, Optical and Electrical properties of the films were investigated by X-ray diffraction, Raman scattering, FT/IR, Optical transmission and Atomic Force Microscopy (AFM). Substrate temperatures ([TSB]) of the films were changed from 100oC to 250oC. It has been revealed the strong dependence on the film’s properties with the substrate temperatures. XRD and Raman measurements were shown that the higher substrate temperature (250oC) exhibits the highest crystalline volume fraction ([ρ] = 95%) and the lowest crystalline size ([Ω] = 3.5 nm) as well, having the highest H-content and the lowest O-content. At 250oC, the lowest mobility and the highest resistivity were also found to be ~37.5 cm2/v.s and 7.35 Ω-cm. Refractive index and the optical energy gap (Eg) were estimated by 3.8 and 1.9 eV having the growth rate of 4.2 nm/min. At 250oC, it was resulted in a blue shift of the absorption edge having uniform grain distributions. Results indicate that in situ hydrogen cleaning effects is prominent and localized orderly high density Si-Si bonds are exhibiting quantum size effects at highest substrate temperature.

scholarly journals The structure and optical properties of CdSe:Cu Thin Films

2009 ◽  
Vol 6 (1) ◽  
pp. 141-149
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Substrate Temperature ◽  
Energy Gap ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
X Ray ◽  
Substrate Temperatures

A polycrystalline CdSe thin films doped with (5wt%) of Cu was fabricated using vacuum evaporation technique in the substrate temperature range(Ts=RT-250)oC on glass substrates of the thickness(0.8?m). The structure of these films are determined by X-ray diffraction (XRD). The X-ray diffraction studies shows that the structure is polycrystalline with hexagonal structure, and there are strong peaks at the direction (200) at (Ts=RT-150) oC, while at higher substrate temperature(Ts=150-250) oC the structure is single crystal. The optical properties as a function of Ts were studied. The absorption, transmission, and reflection has been studied, The optical energy gap (Eg)increases with increase of substrate temperature from (1.65-1.84)eV due to improvement in the structure. The amorphousity of the films decreases with increasing Ts. The films have direct energy gap and the absorption edge was shift slightly towards smaller wavelength for CdSe:Cu thin film with increase of substrate temperature.it was found that the absorption coefficient was decreased with increasing of substrate temperature due to increases the value of(Eg). The CdSe:Cu films showed absorption coefficient in the range (0.94 x104-0.42x104)cm-1at Ts=RT-250 oC. Also the density of state decreases with increasing of substrate temperatures from (0.20-0.07)eV, it is possibly due to the recrystallization by the heating substrate temperatures.. Also the extinction coefficient, refractive index and dielectric constant have been studied.

scholarly journals The Effect of Substrate Temperature on the Band Transition, Cauchy Dispersion and Urbach Energy of Nanostructure CdO Thin Films

2015 ◽  
Vol 58 ◽  
pp. 83-89
Author(s):  
Muneer H. Jadduaa ◽  
Zainab Ali Harbi ◽  
Nadir F. Habubi
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Urbach Energy ◽  
Energy Gap ◽  
Chemical Spray Pyrolysis ◽  
Optical Parameters ◽  
Optical Energy Gap ◽  
Substrate Temperature Increase ◽  
Band Transition ◽  
Cdo Thin Films

Thin films of CdO were prepared by chemical spray pyrolysis (CSP) . The effect of different temperature substrate (300,350,400,450 and 500) °C on some optical parameters has been studied . The transmittance and the optical energy gap were increased from (2.503-2.589) eV ,on the contrary of the rest parameters such as refractive index , real and imaginary parts of dielectric constant and Urbach energy which they were decreased as the substrate temperature increase.

EFFECT OF SUBSTRATE TEMPERATURE ON THE STRUCTURAL AND OPTICAL PROPERTIES OF NiTsPc THIN FILMS

2019 ◽  
Vol 27 (03) ◽  
pp. 1950124 ◽  
Author(s):  
MOHAMMED YARUB HANI ◽  
ADDNAN H. AL-AARAJIY ◽  
AHMED M. ABDUL-LETTIF
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Energy Gap ◽  
Chemical Spray Pyrolysis ◽  
Structural And Optical Properties ◽  
Absorption Bands ◽  
Tauc Plot ◽  
Substrate Temperatures

Nickel(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (NiTsPc) thin films were deposited on glass substrates at different substrate temperatures ([Formula: see text]) by chemical spray pyrolysis (CSP) technique. The substrate temperature varied from 110∘C to 310∘C in 50∘C steps. The substrate surface temperature is the main parameter that determines the film morphology and properties of the thin films. The structural properties of the deposited NiTsPc thin films were investigated by X-ray diffraction (XRD) and from the obtained results, it was shown that depositing thin films using 210∘C as [Formula: see text] results in higher crystallinity. Atomic force microscope (AFM) was employed to obtain the surface topography and to calculate the roughness and grain size. The smoothest thin film surface was obtained when using at 160∘C, while the highest roughness was obtained at 310∘C. The optical properties were investigated by ultraviolet visible (UV-Vis) spectrophotometer and fluorescence spectrophotometer. From the absorption spectra recorded in the wavelength range 190–1100[Formula: see text]nm, two absorption bands were observed, which are known as Soret and Q-band. By observing the absorption spectrum, it can be concluded that the deposited thin films at 110∘C–310∘C have direct energy gap. From Tauc plot relation, the energy gap ([Formula: see text]) was calculated. The values of the energy gap were between 3.05 and 3.14[Formula: see text]eV. It was observed that different [Formula: see text] highly affects the structural and optical properties of the deposited thin films. The crystallinity, grain size, roughness and the optical properties were strongly affected by the different substrate temperatures.

Boron-Doped Nanocrystalline Silicon Thin Films Prepared by PECVD

2012 ◽  
Vol 503 ◽  
pp. 386-390
Author(s):  
Xiu Qin Wang ◽  
Jian Ning Ding ◽  
Ning Yi Yuan ◽  
Shu Bo Wang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Substrate Temperature ◽  
Volume Fraction ◽  
Chemical Vapour ◽  
Nanocrystalline Silicon ◽  
Process Conditions ◽  
Rf Power ◽  
Silicon Thin Films ◽  
Boron Doped

Boron-doped nanocrystalline silicon thin films(p-nc-Si:H) were deposited on glass substrates by plasma enhanced chemical vapour deposition (PECVD) using SiH4/ H2/ B2H6. The effects of substrate temperature, rf power and diborane flow on the microstructure, the electrical properties of nanocrystalline silicon thin films have been investigated. The results show that, increasing substrate temperature, rf power and B2H6flow can improve the conductivity of P-Si thin film. However, exceeding one value, they are not advantageous to improve the conductivity due to the decrystallization of films. Hence, appropriate process conditions are crucial for the preparation of high quality p layer. crystalline volume fraction (Xc) 26.2 %, mean grain size (d) 3.5nm and conductivity 0.374S/cm, p-nc-Si:H thin film was deposited.

scholarly journals Influence of Film Thickness and Heat Treatment on the Physical Properties of Mn Doped Sb2Se3 Nanocrystalline Thin Films

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
I. K. El Zawawi ◽  
Manal A. Mahdy ◽  
E. A. El-Sayad
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Film Thickness ◽  
Energy Gap ◽  
Blue Shift ◽  
Amorphous Structure ◽  
Treatment Temperature ◽  
Optical Energy Gap ◽  
Heat Treated ◽  
Nanocrystalline Thin Films

Nanocrystalline thin films of Sb37.07Mn1.95Se60.98 with different thickness (7, 20, 40, and 80 nm) were successfully prepared via inert gas condensation technique. As-deposited films showed amorphous structure by grazing incident in-plane X-ray diffraction (GIIXD) technique. All films of different thicknesses were heat treated at 433 K for 90 min. The GIIXD pattern of annealed films showed nanocrystalline orthorhombic structure. The effect of thickness of annealed films on the structure and optical properties was studied. Calculated particle sizes are 20.67 and 24.15 for 40 and 80 nm thickness of heat treated film. High resolution transmission electron microscope HRTEM images and their diffraction patterns proved that 40 nm film thickness annealed at different temperature has nanocrystalline nature with observed (high) crystallinity that increases with annealing temperature. Blue shift of optical energy gap was observed from 1.68 to 2 eV with decreasing film thickness from 80 to 7 nm. Film thickness of 40 nm was exposed to different heat treated temperatures from 353 to 473 K to detect its effect on structure and optical and electrical properties. Blue shift from 1.73 to 1.9 eV was observed in its optical band gap due to direct transition as heat treatment temperature decreasing from 473 to 353 K. Electrical conductivity was studied for different heat treated films of thickness 40 nm, and intrinsic conduction mechanism is dominant. The activation energy Ea was affected by heat treatment process.

Electronic Transport in Co-deposited Hydrogenated Amorphous/Nanocrystalline Thin Films

2008 ◽  
Vol 1066 ◽  
Author(s):  
Y. Adjallah ◽  
C. Blackwell ◽  
C. Anderson ◽  
U. Kortshagen ◽  
J. Kakalios
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Nanocrystalline Silicon ◽  
Dark Conductivity ◽  
Mixed Phase ◽  
Bonding Structure ◽  
Hydrogenated Amorphous

ABSTRACTMixed-phase hydrogenated amorphous silicon thin films containing nanocrystalline silicon inclusions have been synthesized in a dual chamber co-deposition system. A PECVD deposition system produces small crystalline silicon particles (3-5 nm diameter) in a flow-through reactor, and injects these particles into a separate capacitively-coupled plasma chamber in which hydrogenated amorphous silicon is deposited. Raman spectroscopy is used to determine the volume fraction of nanocrystals in the mixed phase thin films, while infra-red spectroscopy characterizes the hydrogen bonding structure as a function of nanocrystalline concentration. At a moderate concentration of 5 nm silicon crystallites, the dark conductivity and photoconductivity are consistently found to be higher than in mixed phase films with either lower or higher densities of nanocrystalline inclusions.

scholarly journals Study Influence of Substrate Temperature on Optical Properties of CdS Thin Films Prepared by Chemical Spray pyrolysis

2019 ◽  
Vol 32 (1) ◽  
pp. 6 ◽  
Author(s):  
Karrar Mahdi Saleh
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Spray Pyrolysis ◽  
Energy Gap ◽  
Nitrate Solution ◽  
Chemical Spray Pyrolysis ◽  
Optical Energy Gap ◽  
Chemical Spray ◽  
Cds Thin Films

This study aims to prepare Cadmium Sulphide (CdS) thin films using thermal Chemical Spray Pyrolysis (CSP) on glass of different temperatures substrate from cadmium nitrate solution. Constant thickness was (430 ± 20 nm) and the effect of substrate temperature on the optical properties of prepared thin films. Optical properties have been studied from transmittance and absorbance spectral within wavelengths range (360 - 900 nm). The results show that all the prepared films have a direct electron transitions and optical energy gap between (2.31-2.44 eV). They also show that the transmittance and optical energy gap of films prepared from nitrate solution increase with increasing of substrate temperature, then transmittance start downward with the continued increase in temperature (400, 450) oC.

scholarly journals Electrical and Optical Properties of :H Thin Films Prepared by Thermal Evaporation Method

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
A. A. J. Al-Douri ◽  
M. F. A. Alias ◽  
A. A. Alnajjar ◽  
M. N. Makadsi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Energy Gap ◽  
Dopant Concentration ◽  
Amorphous Film ◽  
Growth Conditions ◽  
Optical Energy Gap ◽  
Electrical And Optical Properties ◽  
Thermal Evaporation Method

Thin a-:H films were grown successfully by fabrication of designated ingot followed by evaporation onto glass slides. A range of growth conditions, Ge contents, dopant concentration (Al and As), and substrate temperature, were employed. Stoichiometry of the thin films composition was confirmed using standard surface techniques. The structure of all films was amorphous. Film composition and deposition parameters were investigated for their bearing on film electrical and optical properties. More than one transport mechanism is indicated. It was observed that increasing substrate temperature, Ge contents, and dopant concentration lead to a decrease in the optical energy gap of those films. The role of the deposition conditions on values of the optical constants was determined. Accordingly, models of the density of states for the :H thin films as pure, doped with 3.5% of Al (p-type) and that doped with 3.5% As (n-type), were proposed.

scholarly journals Effect of Substrate Temperature on Structural and Optical Properties of CdO Thin Films

2014 ◽  
Vol 27 ◽  
pp. 47-55
Author(s):  
Hanan R.A. Ali
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Energy Gap ◽  
Spray Pyrolysis Technique ◽  
Xrd Analysis ◽  
Structural And Optical Properties ◽  
Optical Energy Gap ◽  
Cdo Thin Films

Thin films of CdO have been prepared by spray pyrolysis technique. XRD analysis reveals that all the prepared samples were polycrystalline and have preferred orientation along [111] orientation. The surface topography was determined by AFM which indicate that surface roughness and rms roughness were increased by the increasing of substrate temperature. The optical energy gap were determined and its value lies between (2.4-2.5) eV.

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