scholarly journals Synthesis and Characterisation of Zinc-doped Antimony Selenide

2021 ◽  
pp. 3552-3559
Author(s):  
Thamir A. Jumah ◽  
Kassim M. Wadi ◽  
Riyadh K. Chillab ◽  
Hikmat N. Abdul-Kareem
Keyword(s):  
Band Gap ◽  
Ac Conductivity ◽  
Resistivity Measurement ◽  
Conductivity Measurement ◽  
Solid State Reaction Method ◽  
Dc Resistivity ◽  
Indirect Transition ◽  
Gap Measurement ◽  
Antimony Selenide ◽  
High Absorption

         Antimony selenide substituted with Sb0.4Se0.6 and doped with zinc at three doping ratios (x=0, 0.01 and 0.03) was prepared via the solid state reaction method. The three prepared compositions were reacted thermally at 400 °C for 3 h. The structure of specimens was characterised via X-ray powder diffractometer to obtain the type of crystalline structure and lattice parameters of the prepared specimens, which showed a polycrystalline, orthorhombic structure. Optical characterisation was then achieved via UV-visible spectroscopy to exhibit the transmittance and reflectance spectra and estimate the band gap values of the prepared compositions. The samples showed high absorption spectra at low wavelengths (from 60% to 90%) and low reflectance values (from nearly zero to 17%). The band gap measurement showed an indirect transition, with values ranging from 1.2 eV to 1.23 eV. The electrical characteristics were represented by DC resistivity measurement at low temperature and AC conductivity measurement against frequency. The compositions showed a semiconducting behaviour in DC resistivity and compatible results in AC conductivity.

Self-standing nanoribbons of antimony selenide and antimony sulfide with well-defined size and band gap

2011 ◽  
Vol 22 (17) ◽  
pp. 175705 ◽  
Author(s):  
Rajasekarakumar Vadapoo ◽  
Sridevi Krishnan ◽  
Hulusi Yilmaz ◽  
Carlos Marin
Keyword(s):  
Band Gap ◽  
Antimony Sulfide ◽  
Antimony Selenide

Sol–gel synthesis and optical properties of titanium dioxide thin film

2018 ◽  
Vol 32 (09) ◽  
pp. 1850076 ◽  
Author(s):  
Irfan Ullah ◽  
Shaukat Ali Khattak ◽  
Tanveer Ahmad ◽  
Saman ◽  
Nayab Ali Ludhi
Keyword(s):  
Thin Film ◽  
Titanium Dioxide ◽  
Optical Properties ◽  
Band Gap ◽  
Surface Defects ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Localized States ◽  
Indirect Transition ◽  
Transmission And Absorption

The titanium dioxide (TiO2) is synthesized by sol–gel method using titanium-tetra-iso-propoxide (TTIP) as a starting material, and deposited on the pre-cleaned glass substrate using spin coating technique at optimized parameters. Energy dispersive X-ray (EDX) spectroscopy confirms successful TiO2 growth. The optical properties concerning the transmission and absorption spectra show 85% transparency and 3.28 eV wide optical band gap for indirect transition, calculated from absorbance. The exponential behavior of absorption edge is observed and attributed to the localized states electronic transitions, curtailed in the indirect band gap of the thin film. The film reveals decreasing refractive index with increasing wavelength. The photoluminescence (PL) study ascertains that luminescent properties are due to the surface defects.

Effect of MWCNT addition on the optical band gap of PVA/CS transient biocomposites

2021 ◽  
pp. 002199832110370
Author(s):  
Ömer Bahadır Mergen
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Band Gap ◽  
Optical Band Gap ◽  
Rapid Development ◽  
Measurement Techniques ◽  
Resistivity Measurement ◽  
Optical Parameters ◽  
Optical And Electrical Properties ◽  
Biocomposite Films

In recent years, as a result of increasing environmental concerns, biodegradable materials have gained great attention. With the rapid development of electronic technology, the importance of innovation and development of low-cost, sustainable, transient bioelectronics materials is increasing. In this research, the preparation of Poly(Vinyl Alcohol) (PVA), Chitosan (CS), and Multi-Walled Carbon nanotube (MWCNT) biocomposite films have been described. The solution mixing, ultrasonic mixing, and spin coating techniques were used to prepare the PVA/CS/MWCNT biocomposite thin films. UV–Vis absorption spectroscopy and two-point probe resistivity measurement techniques were used to study the optical and electrical properties of the biocomposite thin films. Optical band gap energies ( Eg) of PVA/CS/MWCNT biocomposites were obtained using the Tauc and Absorbance Spectrum Fitting (ASF) methods. Results obtained with both methods were found to be exactly the same. Experimental results have shown that with increasing MWCNT concentration, electrical conductivity (σ) increases from 1.75x10−16 S to 2.94x10−3 S, and Eg decreases significantly. At the same time, the fundamental optical parameters such as band tail (Urbach) energy ( Eu), refractive index ( n), absorption ( α), and extinction ( k) coefficient of the PVA/CS/MWCNT biocomposites were investigated in the UV-VIS range. The improvement observed in the optical and electrical properties of PVA/CS/MWCNT biocomposite films shows that these composites could be used as bioelectronics materials.

Design of an AC Conductivity Measurement Setup for Sensor Materials Characterization

2014 ◽  
Vol 4 (2) ◽  
pp. 1-7
Author(s):  
Nisha Rajappan ◽  
K.N. Madhusoodanan
Keyword(s):  
Material Characterization ◽  
Ac Conductivity ◽  
Gas Sensing ◽  
Conductivity Measurement ◽  
Sensor Material ◽  
Semiconductor Gas Sensor ◽  
Sensor Materials ◽  
Set Up ◽  
Sensing Characteristics ◽  
Conductivity Cell

AC conductivity measurement can be an effective method for the study of sensor material characteristics for gas sensing. The authors have designed and fabricated a sensitive set up for sensor material characterization using ac conductivity measurement. The set up fabricated is employed for bulk samples. AC conductivity cell with cold fingertip that can facilitate measurement in the range 80 K to 500 K has been fabricated. The necessary vacuum lines and gas feed throughs are provided in order to study the gas sensing characteristics of semiconductor gas sensor materials. A programmable PID temperature controller and the necessary signal conditioning circuits are designed and incorporated into the system. AC conductivity measurement is carried out using Fluke PM 6306 impedance analyzer.

Research on Binary Solution Concentration Detection Method Based on Photonic Band Gap Measurement

2015 ◽  
Vol 52 (6) ◽  
pp. 061603
Author(s):  
阿不都热苏力 Abuduresuli ◽  
帕力哈提 Palihati ◽  
地力夏提 Dilixiati
Keyword(s):  
Band Gap ◽  
Detection Method ◽  
Photonic Band Gap ◽  
Binary Solution ◽  
Solution Concentration ◽  
Gap Measurement ◽  
Photonic Band

scholarly journals Optical properties of CuSe thin films - band gap determination

2017 ◽  
Vol 49 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Milica Petrovic ◽  
Martina Gilic ◽  
Jovana Cirkovic ◽  
Maja Romcevic ◽  
Nebojsa Romcevic ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Room Temperature ◽  
Nir Spectroscopy ◽  
Copper Selenide ◽  
Photoluminescence Spectra ◽  
Indirect Transition ◽  
Direct Transition ◽  
Scanning Electron

Copper selenide thin films of three different thicknesses have been prepared by vacuum evaporation method on a glass substrate at room temperature. The optical properties of the films were investigated by UV-VIS-NIR spectroscopy and photoluminescence spectroscopy. Surface morphology was investigated by field-emission scanning electron microscopy. Copper selenide exhibits both direct and indirect transitions. The band gap for direct transition is found to be ~2.7 eV and that for indirect transition it is ~1.70 eV. Photoluminescence spectra of copper selenide thin films have also been analyzed, which show emission peaks at 530, 550, and 760 nm. The latter corresponds to indirect transition in investigated material.

SHIFT OF BAND GAP FROM DIRECT TO INDIRECT AND OPTICAL RESPONSE OF LiF UNDER PRESSURE

2013 ◽  
Vol 27 (09) ◽  
pp. 1350061 ◽  
Author(s):  
A. SAJID ◽  
G. MURTAZA ◽  
A. H. RESHAK
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Lithium Fluoride ◽  
Pressure Range ◽  
Pressure Effect ◽  
Indirect Transition ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap

We hereby are reporting the transition pressure at which lithium fluoride ( LiF ) compound transforms from direct band gap to indirect band gap insulator on the basis of FP-LAPW calculations. The fundamental band gap of LiF compound suffers direct to indirect transition at a pressure of 70 GPa. The study of the pressure effect on the optical properties e.g. dielectric function, reflectivity, refractive index and optical conductivity of LiF in the pressure between 0–100 GPa, shows that this pressure range is very critical for LiF compound as there are significant changes in the optical properties of this compound.

Seepage Monitoring of an Embankment Dam Using Resistivity Method: A Case Study of LUSI Mud Volcano P.79 - P.82 Embankment

2015 ◽  
Vol 771 ◽  
pp. 213-217 ◽  
Author(s):  
Alwi Husein ◽  
Bagus Jaya Santosa ◽  
Ayi Syaeful Bahri
Keyword(s):  
Water Level ◽  
Resistivity Measurement ◽  
Mud Volcano ◽  
Dc Resistivity ◽  
Embankment Dam ◽  
Water Seepage ◽  
Resistivity Method ◽  
Embankment Height ◽  
Non Destructive

Since the Lusi Mud volcano erupts in Sidoarjo, East Java, on May 2006, soil embankments have been built to keep hot mud within the ponds. Unfortunately, since the embankments were sitting on a poorly weak ground, land subsidence intensively occurred around the embankments. These subsidences are mainly caused by water seepage penetrating the embankment. To observe the part of the embankment that is vulnerable to water seepage, DC Resistivity method, being a non-destructive and versatile method, is used to monitor the subsurface condition of the embankment. P.79 - P.82 embankment, which has collapsed on December 2010 is highlighted in this study because it has the lowest height of all part the embankment, directly adjacent with water from the mud volcano in the inside and field crop on the outside. The research will show the fluctuating results of the water seepage in the embankment during the timeline of February 2012 - October 2013 which, unlike the result of another area, is highly affected by the water level at each measurement. The embankment height during each DC Resistivity measurement is also measured to compare the subsurface result with the condition on the surface. The resistivity subsurface cross section shows increasing water seepage in each measurement (February 2012, July 2012 and October 2013). Alarming seepage level displayed in December 2012 which is presumably triggered by the increase of water level during rainy season is also followed by cracks occurred in the surface.

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