Research Article
Ab-initio Study of the Optoelectronic Properties of a Semiconductor Under the Influence of an External Electric Field: The Case of Silicon (Si)
Issoufou Arzika Alio,
Amadou Arifa Hassan*
,
Aboubacar Almoustapha
Issue:
Volume 15, Issue 1, March 2026
Pages:
1-7
Received:
21 January 2026
Accepted:
3 February 2026
Published:
26 February 2026
Abstract: DFT calculations are performed on the structural, electronic, and optical properties of fcc silicon (Si). The plane wave (PW) method using Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) exchange correlation potentials is applied to solve the Kohn-Sham equations. Energy convergence was examined to study ground-state properties. Band structure and total density of states (TDOS) diagrams are plotted from the calculated equilibrium lattice parameters. An electric field on the order of E=0 V/Å and E= 1V/Å is applied to the silicon surface. Band structure and energy density of Si at electric field E=0 V/A and E= 1V/A is studied in this paper. We also studied variation of the Fermi energy of Si as a function of the applied electric field. On simulate real part of the dielectric function ɛ1(ω) and Imaginary part of the dielectric function ɛ2(ω) as a function of the photon energy for Si with electric field E=0 V/Å and E= 1V/Å (10 GV/m). General profiles of the optical spectra under ambient conditions with and without an electric field are calculated. This study shows that applying an electric field normal to the surface of silicon modifies its electronic and optical properties. The band gap of silicon contracts, with the appearance of band degeneracy. The peak amplitude of its absorption coefficient, the dielectric function and the refractive index decrease in the ultraviolet range and increase in the visible range.
Abstract: DFT calculations are performed on the structural, electronic, and optical properties of fcc silicon (Si). The plane wave (PW) method using Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) exchange correlation potentials is applied to solve the Kohn-Sham equations. Energy convergence was examined to study ground-state properties. ...
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Research Article
Isotherm, Kinetic and Thermodynamic Modelling of Biosorption of Methlyene Blue and Rhodamine 6G Dyes into Melon (Cucumeropsis Manni) Husk from Model Wastewater
Onwordi Chionyedua Theresa,
Adetunji Ibrahim Olaniyi,
Borokinni Ridwan Aderenle,
Oyewole Toyib Seun,
Uche Cosmos Chinedu,
Osifeko Olawale Lawrence,
Tovide Oluwakemi Omotunde,
Osundiya Medinat Olubunmi,
Dodo Salimah Wuraola,
Akoro Seide Modupe,
Olowu Rasaq Adewale*
Issue:
Volume 15, Issue 1, March 2026
Pages:
8-21
Received:
26 November 2025
Accepted:
24 February 2026
Published:
10 March 2026
DOI:
10.11648/j.ajpc.20261501.12
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Abstract: The release of unprocessed or moderately treated industrial wastewater, especially from the textile industry, poses significant environmental challenges due to the elevated levels of pollutants such as dyes. This research investigates the use of agricultural waste, specifically Raw Melon Husk (RMH), for the elimination of two different dyes which are Methylene Blue (MB) and Rhodamine 6G (R6G) utilizing the adsorption technique. RMH was characterized using Fourier Transform Infrared Spectroscopy and Scanning Emission Microscopy. Various experimental parameters were optimized, including pH, adsorbent dosage, initial dye concentration, contact time, and temperature. Optimal conditions for Methylene Blue (MB) and Rhodamine 6G (R6G) dyes removal were determined to be at pH 7 and 6, dosage of 1 g/L and 20 g/L, concentration of 30 mg/L and 50 mg/L, and a contact time of 30 minutes and 10 minutes respectively. The adsorption capacity and percentage removal for MB and R6G are 1.1084 mg/g and 94.5% as well as 1.345 mg/g and 94.20% respectively. The Temkin isotherm model best described the equilibrium data (R² = 0.9966) for MB while Langmuir model with R² = 0.9857 fitted best for R6G suggesting a monolayer biosorption capacity of 1.200 mg/g. The kinetics of both dyes followed a pseudo-second-order model with R² of 0.996 and 0.9998 respectively which inferred that the process is diffusion controlled. Thermodynamic studies indicated that the adsorption process for both dyes were exothermic and spontaneous. The melon husk has successfully been used for removing methylene blue and Rhodamine 6G from model wastewater. This study contributed to achieve SDG goals 3 and 6.
Abstract: The release of unprocessed or moderately treated industrial wastewater, especially from the textile industry, poses significant environmental challenges due to the elevated levels of pollutants such as dyes. This research investigates the use of agricultural waste, specifically Raw Melon Husk (RMH), for the elimination of two different dyes which a...
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