scholarly journals Optical and electrical characterization of BixSe1−x thin films

2016 ◽  
Vol 34 (2) ◽  
pp. 460-467
Author(s):  
M.M. Ibrahim ◽  
S.A. Fayek ◽  
G.A.M. Amin ◽  
D.M. Elnagar
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Structural Changes ◽  
High Vacuum ◽  
Electrical Characterization ◽  
Film Surface ◽  
Localized States ◽  
Optical Parameters ◽  
Electrical And Optical Properties ◽  
Evaporation Technique

AbstractBulk samples of the BixSe1-x system with (x = 0, 5, and 10) were prepared using conventional melt quenching technique. Thin films were then deposited by thermal evaporation technique under high vacuum conditions from the prepared bulk samples. Effect of Bi substitution on surface morphology, electrical and optical properties of BixSe1-x thin films was studied. X-ray diffraction studies showed the formation of nanocrystalline clusters at Bi concentration x = 10. Formation of these clusters resulted in a rough surface which was confirmed by AFM measurements. The film surface was smooth, with RMS roughness of 0.0124 nm for Bi5Se95. For Bi10Se90, the RMS roughness increased to 3.93 nm indicating the formation of Bi2Se3 clusters. A simple hot probe technique showed a transition from p-type to n-type due to Bi incorporation. Charge transport mechanisms were investigated by temperature dependent DC electrical conductivity measurements in the temperature range of 209 K to 313 K. Electrical activation energy (ΔE) of the films with different Bi concentrations was found to exhibit a notable change at the p to n transition. At low temperature, the conduction was in reasonable agreement with Mott’s condition of variable range hopping. Mott parameters and the density of localized states near Fermi level were evaluated and correlated with the structural changes resulting from Bi addition. In addition, a red shift of the optical absorption edge of the films under study caused by Bi-Se substitution was observed. Slight changes in the optical parameters were observed with the γ-irradiation. Addition of Bi atoms could be used to tailor the structural, electrical and optical properties of chalcogenide materials such as junctionless photovoltaic devices.

scholarly journals Effect of Thickness on Structural and Optical Properties of Tetra-tert- butyl-2, 3-naphthalocyanine Thin Films

2011 ◽  
Vol 8 (4) ◽  
pp. 1686-1695 ◽  
Author(s):  
I. Dhanya ◽  
C S Menon
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Physical Vapor Deposition ◽  
Band Gap Energy ◽  
Dielectric Constants ◽  
Localized States ◽  
Optical Parameters ◽  
Tert Butyl ◽  
Vapor Deposition Technique ◽  
Physical Vapor Deposition Technique

Amorphous tetra-tert-butyl-2, 3-naphthalocyanine thin films have been deposited using physical vapor deposition technique under a varied thickness by adjusting the coating time. By analyzing the x-ray diffraction, the structure of as deposited films is found to be non-crystalline. Different optical properties of these thin films have been investigated by means of optical absorption and reflection spectra. Various optical constants like band gap energy, Egthe width of band tails of localized states into the gap, EUand steepness parameter, β gets calculated and the variation of different optical parameters like refractive index, extinction coefficient, dielectric constants, optical conductivity and surface and volume energy losses with photon energy are estimated.

scholarly journals Melioration of Electrical and Optical Properties of Al and B Co-Doped ZnO Transparent Semiconductor Thin Films

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1259
Author(s):  
Chien-Yie Tsay ◽  
Shih-Hsun Yu
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Electrical Properties ◽  
Zno Thin Films ◽  
Optical Parameters ◽  
Electrical And Optical Properties ◽  
Semiconductor Thin Films ◽  
Doped Zno ◽  
Transparent Semiconductor ◽  
Co Doped

Undoped, Al-doped and Al-B co-doped ZnO transparent semiconductor thin films were deposited on glass substrates by sol-gel method and spin coating technique. This study investigated the influence of Al (2 at.%) doping and Al (2 at.%)-B (1 or 2 at.%) co-doping on the microstructural, surface morphological, electrical and optical properties of the ZnO-based thin films. XRD analysis indicated that all as-prepared ZnO-based thin films were polycrystalline with a single-phase hexagonal wurtzite structure. The substitution of extrinsic dopants (Al or Al-B) into ZnO thin films can significantly degrade the crystallinity, refine the microstructures, improve surface flatness, enhance the optical transparency in the visible spectrum and lead to a shift in the absorption edge toward the short-wavelength direction. Experimental results showed that the Al-doped and Al-B co-doped ZnO thin films exhibited high average transmittance (>91.3%) and low average reflectance (<10%) in the visible region compared with the ZnO thin film. The optical parameters, including the optical bandgap, Urbach energy, extinction coefficient and refractive index, changed with the extrinsic doping level. Measured results of electrical properties revealed that the singly doped and co-doped samples exhibited higher electron concentrations and lower resistivities than those of the undoped sample and suggested that 2 at.% Al and 1 at.% B were the optimum dopant concentrations for achieving the best electrical properties in this study.

scholarly journals The optical properties of a- (GeS2)100-xGax thin films

2019 ◽  
Vol 11 (21) ◽  
pp. 28-36
Author(s):  
Bushra A. Hasan
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Constants ◽  
Optical Band Gap ◽  
Bulk Material ◽  
Localized States ◽  
Optical Parameters ◽  
Evaporation Technique ◽  
Opposite Manner ◽  
Average Bond

Thin films whose compositions can be expressed by (GeS2)100-xGax (x=0, 6,12,18) formula were obtained by thermal evaporation technique  of bulk material at a base pressure of ~10-5 torr. Optical transmission spectra of the films were taken in the range of 300-1100 nm then the optical band gap, tail width of localized states,  refractive index, extinction coefficient were calculated. The optical constants were found to increase at low concentration of Ga (0 to12%) while they decreases with further addition of Ga. The optical band gap was found to change in opposite manner to that of optical constants. The variation in the optical parameters are explained in terms of average bond energy of the system.

EFFECT OF SUBSTRATE TEMPERATURE ON THE GROWTH AND PROPERTIES OF ZnO:Al THIN FILMS

2012 ◽  
Vol 19 (02) ◽  
pp. 1250014 ◽  
Author(s):  
JINSONG LEI ◽  
YINSHENG ZOU
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Hydrochloric Acid ◽  
Surface Morphology ◽  
Substrate Temperature ◽  
Film Surface ◽  
Dc Magnetron Sputtering ◽  
Electrical And Optical Properties ◽  
Conductive Films ◽  
Influence Of Substrate

ZnO:Al (AZO) transparent conductive films used for solar cells were prepared by DC magnetron sputtering technology. The influence of substrate temperature on the electrical and optical properties of the films was studied. Further, the AZO films prepared were etched in diluted hydrochloric acid. The film surface morphology after etching for different time was researched.

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