scholarly journals Porous Silicon and Indium Doped Zinc Oxide Junctions: Synthesis, Characterization, and Application to Electroluminescent Devices

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
F. Severiano ◽  
G. García ◽  
L. Castañeda ◽  
V. L. Gayou
Keyword(s):  
Zinc Oxide ◽  
Porous Silicon ◽  
Visible Region ◽  
Electrical Characterization ◽  
Precursor Solution ◽  
Infrared Region ◽  
Dip Coating ◽  
Electromagnetic Spectrum ◽  
Sem Images ◽  
Electroluminescent Devices

We report the obtaining of electroluminescent devices (ELD) from porous silicon (PS) and indium doped zinc oxide (ZnO:In) junctions. PS presented photoluminescence (PL) in the visible region of the electromagnetic spectrum. ZnO:In thin film was obtained by dip coating technique. SEM images and IR measurements showed the incorporation of the ZnO:In in the PS structure. Once obtained, the device was optically and electrically characterized. The ELD showed emission in the visible (450–850 nm) and infrared region (900–1200 nm) where it was electrically polarized. The visible emission was detected as luminescent spots on the surface. Electrical characterization was carried out by current-voltage (I-V) curves. The I-V curves showed rectifying behavior. It was related to the quenching of the EL with the process that takes place in the PS when it was immersed in the precursor solution of the ZnO:In.

scholarly journals Electroluminescent Devices Based on Junctions of Indium Doped Zinc Oxide and Porous Silicon

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
F. Severiano ◽  
G. García ◽  
L. Castañeda ◽  
J. M. Gracia-Jiménez ◽  
Heberto Gómez-Pozos ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Porous Silicon ◽  
Spray Pyrolysis Technique ◽  
Visible Region ◽  
Electrical Characterization ◽  
Ultrasonic Spray Pyrolysis ◽  
Hole Injection ◽  
Electroluminescent Devices ◽  
Ultrasonic Spray Pyrolysis Technique ◽  
Ultrasonic Spray

Electroluminescent devices (ELD) based on junctions of indium doped zinc oxide (ZnO:In) and porous silicon layers (PSL) are presented in this work. PSL with different thicknesses and photoluminescent emission, around 680 nm, were obtained by anodic etching. PSL were coated with a ZnO:In film which was obtained by ultrasonic spray pyrolysis technique. Once obtained, this structure was optically and electrically characterized. When the devices were electrically polarized they showed stable electroluminescence (EL) which was presented as dots scattered over the surface. These dots can be seen with the naked eye. The observed EL goes from the 410 to 1100 nm, which is formed by different emission bands. The EL emission in the visible region was around 400 to 750 nm, and the emission corresponding to the infrared part covers the 750 to 1150 nm. The electrical characterization was carried out by current-voltage curves(I-V)which show a rectifying behavior of the devices. Observed electroluminescent dots are associated with the electron-hole injection into quantized states in PS as well as the emission from the ZnO:In film.

scholarly journals Effect of Annealing on Optical Properties of Zinc Oxide Thin Films Prepared by Homemade Spin Coater

2015 ◽  
Vol 15 (2) ◽  
pp. 111-116 ◽  
Author(s):  
Deependra Das Mulmi ◽  
Agni Dhakal ◽  
Buddha Ram Shah
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Band Gap ◽  
Precursor Solution ◽  
Infrared Region ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Gap Energy ◽  
Glass Substrates ◽  
Near Ultraviolet

Zinc oxide (ZnO) thin films were deposited on the ordinary glass substrates by spin coating method. The precursor solution was prepared by mixing zinc acetate dehydrate in appropriate proportions with ethanol and diethanolamine (DEA). The obtained thin films were dried at 200°C for 15 minutes in hot air oven. Crystalline ZnO thin films were achieved following annealing process at temperatures 300°, 400° and 500°C for 2 hours. Thin films as- prepared were studied by X-ray diffraction and UV-visible spectroscopy. The films were transparent from near ultraviolet to infrared region. Optical band gap energy of ZnO was obtained 3.22 eV at 300°C. On annealing at 400° and 500°C, band gap energy was shifted at 3.14 eV and 3.05 eV respectively.DOI: http://dx.doi.org/njst.v15i2.12126Nepal Journal of Science and Technology Vol. 15, No.2 (2014) 111-116

scholarly journals Preparation and spectroscopic analysis of zinc oxide nanorod thin films of different thicknesses

2017 ◽  
Vol 35 (3) ◽  
pp. 501-510 ◽  
Author(s):  
Nasrul Haque Mia ◽  
Sardar Masud Rana ◽  
Firoz Pervez ◽  
Mohammad Reefaz Rahman ◽  
Khalid Hossain ◽  
...  
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Sol Gel ◽  
Hydrothermal Process ◽  
Visible Region ◽  
Hexagonal Structure ◽  
Ultraviolet Region ◽  
Electromagnetic Spectrum ◽  
Axis Orientation ◽  
X Ray

AbstractZinc oxide thin films with different thicknesses were prepared on microscopic glass slides by sol-gel spin coating method, then hydrothermal process was applied to produce zinc oxide nanorod arrays. The nanorod thin films were characterized by various spectroscopic methods of analysis. From the images of field emission scanning electron microscope (FESEM), it was observed that for the film thickness up to 200 nm the formed nanorods with wurtzite hexagonal structure were uniformly distributed over the entire surface substrate. From X-ray diffraction analysis it was revealed that the thin films had good polycrystalline nature with highly preferred c-axis orientation along (0 0 2) plane. The optical characterization done by UV-Vis spectrometer showed that all the films had high transparency of 83 % to 96 % in the visible region and sharp cut off at ultraviolet region of electromagnetic spectrum. The band gap of the films decreased as their thickness increased. Energy dispersive X-ray spectroscopy (EDS) showed the presence of zinc and oxygen elements in the films and Fourier transform infrared spectroscopy (FT-IR) revealed the chemical composition of ZnO in the film.

scholarly journals Synthesis and Characterization of Aluminum Doped Zinc Oxide Nanostructures by Nd:YAG Laser in Liquid

2020 ◽  
pp. 2590-2598
Author(s):  
Khawla S. Khashan ◽  
Ghassan M. Sulaiman ◽  
Sura A. Hussain
Keyword(s):  
Zinc Oxide ◽  
Visible Region ◽  
Laser Pulses ◽  
Deionized Water ◽  
Zinc Oxide Nanostructures ◽  
Zno Nps ◽  
Sem Images ◽  
Oxide Nanostructures ◽  
Aluminum Doped Zinc Oxide

Aluminum doped zinc oxide nanoparticles (AZO) with different doping concentrations were prepared by Nd-YAG laser ablation of target in deionized water. The characterization of these nanoparticles was performed using Fourier transform infrared (FTIR)  spectroscopy,  scanning electron microscopy (SEM) and photoluminance spectroscopy (PL).  FTIR spectra confirmed the formation  of vibrational bonds for ZnO NPs and AZO NPs. SEM images illustrated that the size and shape of the NPs changed with changing the number of laser pulses. Photoluminescence peaks exhibited two emission peaks, one at the UV region and the second in the visible region, which were modified as the number of laser pulses and doping concentration were changed.

scholarly journals Advances in electromagnetic applications and communications

TecnoLógicas ◽  
2018 ◽  
Vol 21 (43) ◽  
pp. 9-13 ◽  
Author(s):  
Erick Reyes-Vera ◽  
David E. Senior ◽  
José Martín Luna-Rivera ◽  
Francisco Eugenio López-Giraldo
Keyword(s):  
Communication Systems ◽  
Visible Region ◽  
Infrared Region ◽  
Electromagnetic Spectrum ◽  
Radio Waves ◽  
Spectrum Radio

Modern communication systems have traditionally exploited three parts of the electromagnetic spectrum: radio waves region, infrared region and visible region, where the evolution in these ranges is always accompanied by the appropriation of new electromagnetic phenomena to build devices with better characteristics. In these three regions great advances have been conducted in recent years. For this reason, in this issue, we call for papers concerning to the major challenges that these technologies may face in the coming years. 

scholarly journals Electronic, Structural, and Optical Structure of Mono-Doped and Co-Doped (210) TiO2 Brookite Surfaces for Application in Dye-Sensitized Solar Cells—A First Principles Study

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3918
Author(s):  
Ratshilumela S. Dima ◽  
Lutendo Phuthu ◽  
Nnditshedzeni E. Maluta ◽  
Joseph K. Kirui ◽  
Rapela R. Maphanga
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Dye Sensitized Solar Cells ◽  
Visible Region ◽  
Electromagnetic Spectrum ◽  
Doped Tio2 ◽  
Dye Sensitized ◽  
Sensitized Solar Cells ◽  
Co Doped ◽  
Optical Structure

Titanium dioxide (TiO2) polymorphs have recently gained a lot of attention in dye-sensitized solar cells (DSSCs). The brookite polymorph, among other TiO2 polymorphs, is now becoming the focus of research in DSSC applications, despite the difficulties in obtaining it as a pure phase experimentally. The current theoretical study used different nonmetals (C, S and N) and (C-S, C-N and S-N) as dopants and co-dopants, respectively, to investigate the effects of mono-doping and co-doping on the electronic, structural, and optical structure properties of (210) TiO2 brookite surfaces, which is the most exposed surface of brookite. The results show that due to the narrowing of the band gap and the presence of impurity levels in the band gap, all mono-doped and co-doped TiO2 brookite (210) surfaces exhibit some redshift. In particular, the C-doped, and C-N co-doped TiO2 brookite (210) surfaces exhibit better absorption in the visible region of the electromagnetic spectrum in comparison to the pure, S-doped, N-doped, C-S co-doped and N-S co-doped TiO2 brookite (210) surfaces.

Photocatalytic Degradation of Methylene Blue by NiO Thin Films under Solar Light Irradiation

2019 ◽  
Vol 56 ◽  
pp. 152-157 ◽  
Author(s):  
Abdelouahab Noua ◽  
Hichem Farh ◽  
Rebai Guemini ◽  
Oussama Zaoui ◽  
Tarek Diab Ounis ◽  
...  
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Sol Gel ◽  
Visible Region ◽  
Optical Transmittance ◽  
Dip Coating ◽  
Light Irradiation ◽  
Solar Light ◽  
Solar Light Irradiation

Nickel oxide (NiO) thin films were successfully deposited by sol-gel dip-coating method on glass substrates. The structural, morphological and optical properties in addition to the photocatalytic activity of the prepared films were investigated. The results show that the films have a polycrystalline NiO cubic structure with dense NiO grains and average optical transmittance in the visible region. The photocatalytic properties of the films were studied through the degradation of methylene blue and 89% of degradation was achieved for 4.5h of solar light irradiation exposure which indicates the capability of NiO photocatalytic activity.

scholarly journals Fabrication of Porous Silicon Based Humidity Sensing Elements on Paper

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Tero Jalkanen ◽  
Anni Määttänen ◽  
Ermei Mäkilä ◽  
Jaani Tuura ◽  
Martti Kaasalainen ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Smart Cities ◽  
Low Cost ◽  
Electrical Characterization ◽  
Fabrication Process ◽  
Sensing Element ◽  
Paper Substrate ◽  
Roll To Roll ◽  
Silver Electrodes ◽  
Silicon Based

A roll-to-roll compatible fabrication process of porous silicon (pSi) based sensing elements for a real-time humidity monitoring is described. The sensing elements, consisting of printed interdigitated silver electrodes and a spray-coated pSi layer, were fabricated on a coated paper substrate by a two-step process. Capacitive and resistive responses of the sensing elements were examined under different concentrations of humidity. More than a three orders of magnitude reproducible decrease in resistance was measured when the relative humidity (RH) was increased from 0% to 90%. A relatively fast recovery without the need of any refreshing methods was observed with a change in RH. Humidity background signal and hysteresis arising from the paper substrate were dependent on the thickness of sensing pSi layer. Hysteresis in most optimal sensing element setup (a thick pSi layer) was still noticeable but not detrimental for the sensing. In addition to electrical characterization of sensing elements, thermal degradation and moisture adsorption properties of the paper substrate were examined in connection to the fabrication process of the silver electrodes and the moisture sensitivity of the paper. The results pave the way towards the development of low-cost humidity sensors which could be utilized, for example, in smart packaging applications or in smart cities to monitor the environment.

The Photoluminescence Enhancement and Stability of Porous Silicon by Cathodic Reduction and Acid Treatment

2014 ◽  
Vol 887-888 ◽  
pp. 458-461
Author(s):  
Chang Qing Li ◽  
Kun Wang ◽  
Pei Jia Liu ◽  
Qi Ming
Keyword(s):  
Electron Microscope ◽  
Porous Silicon ◽  
Acid Treatment ◽  
Cathodic Reduction ◽  
Luminescence Properties ◽  
Sem Images ◽  
Photoluminescence Enhancement ◽  
The Stability ◽  
Scanning Electron ◽  
Cathode Reduction

Porous silicon (PSi) was fabricated by using electrochemical anodic etching method. Then acid treatment and cathode reduction treatment were employed to improve the luminescence properties and stability of PSi material. Photoluminescence (PL) measurements and scanning electron microscope (SEM) were used to observe the luminescence properties and microstructure of samples, respectively. The results of PL measurements showed that the PL intensity and the stability of luminescence of samples after cathodic reduction and acid treatment were significantly improved. The SEM images showed that the porosity of PSi may be increased through the cathodic reduction treated.

Sign in / Sign up

Export Citation Format

Share Document