OPTICAL ENERGY-GAP VARIATION IN InAs–InSb ALLOYS

Homogeneous samples of InAs–InSb alloys have been produced by very slow directional freezing and zone recrystallization methods, and used for the determination of values of the optical energy gap Eg by standard infrared transmission measurements. Room-temperature values of Eg have been obtained in the composition ranges 0–20 and 55–100 mol % InSb and the variation of Eg with temperature from 90 °K to 360 °K for alloys in the composition ranges 0–20 and 80–100 mol % InSb. Approximate room-temperature values of Eg for alloys in the range 20–55 mol % InSb have been obtained by diffuse reflectivity measurements on annealed powders.The value of Eg is found to fall as either compound is added to the other and the room-temperature values show a minimum of 0.10 eV at approximately 60 mol % InSb.

Download Full-text

Optical energy gap variation in GaxIn1−x As alloys

Canadian Journal of Physics ◽

10.1139/p68-023 ◽

1968 ◽

Vol 46 (2) ◽

pp. 157-159 ◽

Cited By ~ 24

Author(s):

John C. Woolley ◽

Mathew B. Thomas ◽

Alan G. Thompson

Keyword(s):

Thermoelectric Power ◽

Fermi Energy ◽

Room Temperature ◽

Energy Gap ◽

Empirical Equations ◽

Optical Energy Gap ◽

Optical Energy ◽

Good Agreement ◽

Gap Values

Room-temperature optical energy-gap values have been determined for GaxIn1−x As alloys, and have been corrected, where necessary, for the Burstein effect by finding Fermi energy values from thermoelectric power data. The results show good agreement with the empirical equations given previously for mixed III–V alloys.

Download Full-text

DEPENDENCE OF THE OPTICAL AND ELECTRICAL PROPERTIES OF CHEMICALLY ANNEALED VACUUM-DEPOSITED a-Si:H FILMS ON THE DEPOSITION RATE

Modern Physics Letters B ◽

10.1142/s0217984913500152 ◽

2012 ◽

Vol 27 (02) ◽

pp. 1350015

Author(s):

AHMED M. EL-NAGGAR

Keyword(s):

Activation Energy ◽

Electrical Properties ◽

Deposition Rate ◽

Room Temperature ◽

Energy Gap ◽

Dark Conductivity ◽

Optical Parameters ◽

Optical And Electrical Properties ◽

Optical Energy Gap ◽

Optical Energy

The influence of the deposition rate of chemically annealed vacuum-deposited a-Si : H films on its optical and electrical properties was studied. The optical parameters were studied using spectrophotometric measurements of the film transmittance in the wavelength range 200–3000 nm. It was found that with increasing the silicon deposition rate from 0.09 to 0.23 nm/s, the refractive index, n, decreases from 3.78 to 3.45 at 1.5 μm, and the optical energy gap, Eg, decreases from 1.74 to 1.66 eV, while the Urbach parameter, ΔE, increases from 77 to 99 meV. The dark conductivity was measured at temperatures descending from 480 to 170 K. It was found that the room temperature dark conductivity values decreased from 1.11 × 10-6 (Ω⋅ cm )-1 to 2.08 × 10-10 (Ω⋅ cm )-1 with increasing the deposition rate from 0.09 to 0.23 nm/s respectively, while the activation energy Ea increased from 0.53 to 0.84 eV with increasing deposition rate. As a result, a good quality a-Si : H film with optical energy gap of 1.74 eV, Urbach parameter of 77 meV, dark conductivity of 1.11 × 10-6 (Ω⋅ cm )-1, and activation energy of 0.53 eV was successfully prepared at a low deposition rate of 0.09 nm/s.

Download Full-text

Determination of the optical energy gap of Ge1−xSnx alloys with 0

Applied Physics Letters ◽

10.1063/1.1758772 ◽

2004 ◽

Vol 84 (22) ◽

pp. 4532-4534 ◽

Cited By ~ 69

Author(s):

H. Pérez Ladrón de Guevara ◽

A. G. Rodrı́guez ◽

H. Navarro-Contreras ◽

M. A. Vidal

Keyword(s):

Energy Gap ◽

Optical Energy Gap ◽

Optical Energy

Download Full-text

Determination of Optical Energy Gap for Copper oxide at Different Temperatures

International Journal of Advanced Engineering Research and Science ◽

10.22161/ijaers.5.3.33 ◽

2018 ◽

Vol 5 (3) ◽

pp. 255-258 ◽

Cited By ~ 2

Author(s):

Wasil Abdalgader Abdalla Alhassan ◽

Ismael. A. Wadi

Keyword(s):

Copper Oxide ◽

Energy Gap ◽

Optical Energy Gap ◽

Optical Energy ◽

Different Temperatures

Download Full-text

Temperature Dependence of the Optical Band Gap and Optical Parameters of Tetramethyl Ammonium Tetrachlorozincate (TMA)2ZnCl4 single Crystals Around the Normal and Incommensurate Phase Transitions

The Open Materials Science Journal ◽

10.2174/1874088x01509010162 ◽

2015 ◽

Vol 9 (1) ◽

pp. 162-172 ◽

Cited By ~ 1

Author(s):

A. Abu El-Fadl ◽

A.M. Nashaat

Keyword(s):

Single Crystals ◽

Room Temperature ◽

Energy Gap ◽

Optical Transition ◽

Incommensurate Phase ◽

Spectral Studies ◽

Optical Parameters ◽

Optical Energy Gap ◽

Optical Energy ◽

Increasing Temperature

Single crystals of tetramethylammonium tetrachlorozincate [N(CH3)4]ZnCl4 abbreviated hereafter as (TMA)2ZnCl4 were grown using the slow evaporation technique at 315 K. The X-ray powder diffraction patterns indicated that [N(CH)]ZnCl belongs to the orthorhombic system with Pmcn symmetry at room temperature. The lattice constants are found to be a= 12.360 Å, b= 15.687 Å and c= 8.985 Å. The values were in good agreement with the values in previous studies. Ultraviolet–visible–near-infrared (UV–Vis–NIR) spectral studies were carried out in the temperature range 276–307 K. This range of temperature involves two phase transition temperatures (Ti=296 K) from normal (parent) to incommensurate phase and (T=279 K) from incommensurate to commensurate-ferroelectric phase. The cut off wavelength was found to be 195.016 nm at room temperature. The optical transmittance increases with increasing temperature, and the cut off shifts to higher wavelengths. Analysis reveals that the type of optical transition is the indirect allowed one. The optical energy gap (Eg) has the value of 5.903 eV at room temperature. The value of optical energy gap (Eg) decreases with increasing temperature. The changes in the values of the cut off wavelength and optical energy gap (Eg) with changing the temperature were found to take different rates at the two phases under study, besides anomalous takes place at Ti and Tc. The absorption coefficient (α) as a function of the incident photon energy shows an exponential behavior near the absorption edge which suggests that the Urbach rule is obeyed and indicated the formation of a band tail. Urbach parameters were calculated at different temperatures and the frequencies of effective phonons and electron–phonon interaction constants were determined for various phases.

Download Full-text

SYNTHESIS OF CARBON DOTS (CDS) AND DETERMINATION OF OPTICAL GAP ENERGY WITH TAUC PLOT METHOD

Jambura Physics Journal ◽

10.34312/jpj.v3i2.11235 ◽

2021 ◽

Vol 3 (2) ◽

pp. 73-86

Author(s):

Jumardin Jumardin ◽

Akhiruddin Maddu ◽

Koekoeh Santoso ◽

Isnaeni Isnaeni

Keyword(s):

Carbon Dots ◽

Energy Gap ◽

Indirect Transition ◽

Optical Energy Gap ◽

Time Duration ◽

Optical Energy ◽

Laser Ablation Method ◽

Tauc Plot ◽

Optical Gap Energy

Carbon Dots (CDs) which have been synthesized using the laser ablation method show the presence of UV-Vis absorption in the wavelength range of 303 nm to 333 nm for absorbance and 495 nm to 503 nm for fluorescence. Changes in the time duration 1, 2, 3 hours of CDs resulted in changes in the optical energy gap. The optical energy gap valuesare distinguished by the type of indirect transition (n=2) is 3.40 eV (1 hour), 3.15 eV (2 hour), 2.85 eV (3 hour) and direct transition (n=1/2) is 2.58 eV (1 hour), 2.31 eV (2 hour), 1.70 eV (1 hour).

Download Full-text