Optical Characterization of Hydrogenated Silicon Films in the Extended Energy Range

1995 ◽  
Vol 406 ◽  
Author(s):  
T. Globus ◽  
S. J. Fonash ◽  
G. Gildenblat
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Absorption Coefficient ◽  
Film Growth ◽  
Optical Measurement ◽  
Specular Reflection ◽  
Device Fabrication ◽  
Hydrogenated Silicon ◽  
Wide Range

AbstractThis work introduces a new interference technique for the diagnostic characterization of hydrogenated silicon thin films. The interference technique is based on new self-consistent data analysis algorithms for simultaneous optical transmission and specular reflection using exact interference equations for the system of a film on a substrate. It provides a quick non-destructive optical measurement of absorption coefficient and refractive index spectra of amorphous silicon (a-Si:H) and polycrystalline silicon (poly-Si:H) thin films in a wide range of the incident photon energies (0.5–3.5 eV). This non-contacting, high sensitivity method is a powerful probe of various material properties including thickness, refractive index and absorption spectra, hydrogen content, alloy fraction, energies of localized defect states and their concentrations. Experimental results for optical study of hydrogenated Si films indicate that the proposed method makes possible high precision measurements of the absorption in the region near the fundamental edge. In this region the absorption coefficient varies over several orders of magnitude. Also, the absorption related to impurities and defects in the subgap energy region at least from 102 cm−1 can be detected. As a result, the interference technique shows promise in providing feedback for monitoring film growth and device fabrication processes.

Energy Levels of Defects in a-Si:H From Optical and Electrical Characteristics

1996 ◽  
Vol 424 ◽  
Author(s):  
T. Globus
Keyword(s):  
Thin Films ◽  
Energy Levels ◽  
Thin Film Transistor ◽  
Close Correlation ◽  
Device Fabrication ◽  
Defect States ◽  
Optical Interference ◽  
Hydrogenated Silicon ◽  
Transfer Characteristics ◽  
Wide Range

AbstractTwo novel characterization techniques for hydrogenated silicon thin films have been recently proposed which show promise in providing critical feedback for evaluating materials and monitoring the device fabrication process. The first technique is the optical interference spectroscopy for a quick non-destructive measurement of absorption coefficient and refractive index spectra of amorphous- and poly-Si thin films in a wide range of the incident photon energies (0.5–3.5 eV) [1]. By using this technique, the absorption related to defects in the subgap energy region has been determined for device quality thin films. The second technique is the novel version of the field effect conductivity (FEC) method for the direct density-of-states (DOS) determination from analysis of thin film transistor (TFT) quasi-static transfer characteristics [2]. This sensitive, fast, and easy to use, method makes it possible to resolve fine-scale features in the midgap DOS of a-Si:H. In this work, data from two methods of spectroscopy are analyzed together. Very close correlation of results is demonstrated which provides a unique opportunity to identify midgap defect states and to understand the fundamental physics of hydrogenated silicon films. The energy map of defect states in the upper half of a-Si:H bandgap is presented. These results permits to use TFT transfer characteristics and optical interference technique measurements as effective tools to control the quality of TFF manufacturing process.

scholarly journals Characterization of As-Prepared (PMMA-PVA)/CuO-NPs Hybrid Nanocomposite Thin Films

2021 ◽  
Author(s):  
Ahmad Alsaad ◽  
Ahmad Ahmad ◽  
Abdul Raouf Al Dairy ◽  
Issam A. Qattan ◽  
Shatha Al Fawares ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Bandgap ◽  
Bandgap Energy ◽  
Polymeric Thin Films ◽  
Cuo Nps ◽  
Wide Range ◽  
Nanocomposite Thin Films ◽  
Optical Bandgap Energy

We report the synthesis and characterization of Poly Methyl-Meth-Acrylate (PMMA)/Poly vinylalcohol (PVA) polymeric blend doped with different concentrations of Copper oxide (CuO) nanoparticles (NPs). The (PMMA-PVA)/CuO nanocomposite hybrid thin films (wt. % = 0%, 2%, 4%, 8%, and 16%) of CuO NPs are deposited on glass substrates via dip-coating technique. The transmittance (T%), reflectance (R%), the absorption coefficient (α), the optical constants [refractive index (n), extinction coefficient (k)], optical dielectric functions [ɛ',ɛ''] are investigated and interpreted. Tauc, Urbach, Spitzer-Fan, and Drude models are employed to calculate the optical bandgap energy (Eg) and the optoelectronic parameters of the nanocomposite thin films. The refractive index and optical bandgap energy of of (PMMA-PVA) polymeric thin film are found to be (1.5 to 1.85) and 4.101 eV, respectively. Incorporation of specific concentrations of CuO-NPs in (PMMA-PVA) polymeric thin films leads to a noticeable decrease in the optical bandgap energy and to an increase of the refractive index. Moreover, Fourier Transform Infrared Spectroscopy (FTIR) transmittance spectra are measured and analyzed for undoped and doped polymeric thin films to pinpoint the major vibrational modes in the spectral range (500 and 4000 cm-1), as well as, the nature of network bonding in both systems. Thermal stability of thin films is investigated by performing thermogravimetric analysis (TGA). The TGA thermograms confirm that both doped polymeric thin films are thermally stable at temperatures below 110°C which enables them to be attractive for a wide range of optical and optoelectronic applications. Our results indicate that optical, vibrational and thermal properties of both polymeric thin films can be tuned for specific applications by the appropriate corporation of particular concentrations of CuO-NPs.

scholarly journals Preparation and Studying the Optical Properties of (Sb2o3) Thin Films

2018 ◽  
Vol 26 (10) ◽  
pp. 249-256
Author(s):  
Waleed Khalid Kadhim
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Thermal Evaporation ◽  
Glass Slide ◽  
Antimony Trioxide ◽  
Hot Plate ◽  
Different Thickness

In this paper I present the preparation of (Sb2o3) thin films using thermal evaporation in vacuum, procedure with different thickness  (100 ,150 ,200 ,and 250) nm, by using ( hot plate) from Molybdenum matter at temperature in ( 9000c) and the period of time (15mint) ,the prepared in a manner thermal evaporation in a vacuum and precipitated on glass bases, pure Antimony Trioxide (sb2o3 ) thin films with various condition have been successfully deposited by (T.E.V) on glass slide substrates. The substrates temperature of about 100oC and the vacuum of about 10-6 torr, to investigated oxidation of evaporated, measure spectra for prepared films in arrange of wavelength (250 – 1100 nm). The following optical properties have been calculated: the absorption coefficient, the forbidden (Eg) for direct and indirect transitions "absorbance, refractive index,  extinction coefficient, real and imaginary parts" of the dielectric constant.

scholarly journals Deposition Time induced Structural and Optical Properties of Lead Tin Sulphide Thin Films

2021 ◽  
pp. 455-458
Author(s):  
J. Damisa ◽  
J. O. Emegha ◽  
I. L. Ikhioya
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Tin Oxide ◽  
Deposition Time ◽  
Deposition Process ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Prepared Material

Lead tin sulphide (Pb-Sn-S) thin films (TFs) were deposited on fluorine-doped tin oxide (FTO) substrates via the electrochemical deposition process using lead (II) nitrate [Pb(NO3)2], tin (II) chloride dehydrate [SnCl2.2H2O] and thiacetamide [C2H5NS] precursors as sources of lead (Pb), tin (Sn) and sulphur (S). The solution of all the compounds was harmonized with a stirrer (magnetic) at 300k. In this study, we reported on the improvements in the properties (structural and optical) of Pb-Sn-S TFs by varying the deposition time. We observed from X-ray diffractometer (XRD) that the prepared material is polycrystalline in nature. UV-Vis measurements were done for the optical characterizations and the band gap values were seen to be increasing from 1.52 to 1.54 eV with deposition time. In addition to this, the absorption coefficient and refractive index were also estimated and discussed.

scholarly journals Annealing Effect on Some Optical Properties of Cr2O3 Thin Films Prepared by Spray Pyrolysis Technique

2011 ◽  
Vol 8 (2) ◽  
pp. 561-565
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Spray Pyrolysis ◽  
Annealing Temperature ◽  
Spray Pyrolysis Technique ◽  
Annealing Effect ◽  
Before And After

Cr2O3 thin films have been prepared by spray pyrolysis on a glass substrate. Absorbance and transmittance spectra were recorded in the wavelength range (300-900) nm before and after annealing. The effects of annealing temperature on absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant and optical conductivity were expected. It was found that all these parameters increase as the annealing temperature increased to 550°C.

scholarly journals Optical constants of sputtered beryllium thin films determined from photoabsorption measurements in the spectral range 20.4–250 eV

2020 ◽  
Vol 27 (1) ◽  
pp. 75-82
Author(s):  
Mikhail Svechnikov ◽  
Nikolay Chkhalo ◽  
Alexey Lopatin ◽  
Roman Pleshkov ◽  
Vladimir Polkovnikov ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Synchrotron Radiation ◽  
Initial Data ◽  
Absorption Coefficient ◽  
Energy Range ◽  
Transmission Coefficient ◽  
Radiation Source ◽  
Optical Constants ◽  
Free Standing

In this work, the refractive index of beryllium in the photon energy range 20.4–250 eV was experimentally determined. The initial data include measurements of the transmittance of two free-standing Be films with thicknesses of 70 nm and 152 nm, as well as reflectometric measurements of similar films on a substrate. Measurements were carried out at the optics beamline of the BESSY II synchrotron radiation source. The absorption coefficient β was found directly from the transmission coefficient of the films, and the real part of the polarizability δ was calculated from the Kramers–Kronig relations. A comparison is carried out with results obtained 20 years ago at the ALS synchrotron using a similar methodology.

Surface characterization of sputtered N:TiO2 thin films within a wide range of dopant concentration

2014 ◽  
Vol 40 (7) ◽  
pp. 9989-9995 ◽  
Author(s):  
A.V. Manole ◽  
M. Dobromir ◽  
R. Apetrei ◽  
V. Nica ◽  
D. Luca
Keyword(s):  
Thin Films ◽  
Surface Characterization ◽  
Dopant Concentration ◽  
Wide Range

Optimal Preparation and Characterization of Sputtered Y2O3 Films on Sapphire Substrates

2014 ◽  
Vol 602-603 ◽  
pp. 266-269 ◽  
Author(s):  
Gui Gen Wang ◽  
Hong Liang Qian ◽  
Qing Tao Li ◽  
Guo Shuang Qin ◽  
Lin Luo
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Deposition Velocity ◽  
Rf Power ◽  
Sapphire Substrates ◽  
Elastic Module ◽  
Preparation Conditions ◽  
Composition Structure ◽  
Sputtering Pressure

Normal 0 7.8 磅 0 2 false false false MicrosoftInternetExplorer4 It is necessary to prepare compressive films on sapphire window for preventing its high-temperature failure. In this study, the yttrium oxide (Y2O3) thin films were deposited on the sapphire substrates by RF reactive magnetron sputtering with varying sputtering pressure. The as-deposited Y2O3films were also annealed. The composition, structure, refractive index and mechanical properties of the films were systematically analyzed by XPS, XRD, ellipsometry and nanoindention method, respectively. The influences of sputtering pressure on the deposition velocity and the refractive index were investigated. It can obtain desirable Y2O3thin films for the preparation conditions (sputtering pressure: 10Pa, substrate temperature: 500°C, RF power: 200W) after annealing in O2at 500°C for 1h. The refractive index and hardness both have the maximum value (1.8337 and 3.98 GPa), respectively. The elastic module has the minimum value (109.24 GPa). It is promising for the Y2O3film as the underlayer of protective coating of sapphire windows. <object classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui> st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:普通表格; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0pt 5.4pt 0pt 5.4pt; mso-para-margin:0pt; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

ATOMIC LAYER DEPOSITION OF SiO2 USING CATALYZED AND UNCATALYZED SELF-LIMITING SURFACE REACTIONS

1999 ◽  
Vol 06 (03n04) ◽  
pp. 435-448 ◽  
Author(s):  
J. W. KLAUS ◽  
O. SNEH ◽  
A. W. OTT ◽  
S. M. GEORGE
Keyword(s):  
Thin Films ◽  
Dielectric Breakdown ◽  
Substrate Surface ◽  
Surface Reactions ◽  
Atomic Layer ◽  
Device Fabrication ◽  
Initial Substrate ◽  
Wide Range ◽  
Limiting Surface ◽  
Layer Control

SiO 2 thin films were deposited with atomic layer control using self-limiting surface reactions. The SiO 2 growth was achieved by separating the binary reaction SiCl 4+ 2H 2 O → SiO 2+ 4HCl into two half-reactions. Successive application of the half-reactions in an ABAB… sequence produced atomic-layer-controlled SiO 2 deposition. SiO 2 films were grown at temperatures of 600–800 K, with SiCl 4 and H 2 O reactant exposures of ~109 L ( 1 L = 10-6 Torr s). Employing pyridine ( C 5 H 5 N ) as a catalyst, the SiO 2 films could be deposited at much lower temperatures and reactant exposures. The pyridine catalyst lowered the required SiO 2 deposition temperature from 600 K to 300 K and reduced the reactant exposure required for complete reactions from ~109 L to ~ 104 L. In addition, the SiO 2 growth rates increased from 0.75 Å per AB cycle at 800 K to 2.1 Aring; per AB cycle at 300 K. The deposited films were stoichiometric SiO 2 and were extremely flat, with a roughness nearly identical to the initial substrate surface. The films also displayed dielectric breakdown strengths similar to thermally deposited SiO 2 films. The ability to deposit conformal SiO 2 thin films with atomic layer control over a wide range of temperatures should find numerous applications in thin film device fabrication.

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