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Article
Publication date: 22 July 2014

G. Golan, A. Axelevitch and Jacob Azoulay

This paper presents an experimental investigation of photovoltaic (PV) properties in heterostructures consisting of indium oxide and amorphous silicon thin films, grown on a…

Abstract

This paper presents an experimental investigation of photovoltaic (PV) properties in heterostructures consisting of indium oxide and amorphous silicon thin films, grown on a single crystalline p-type silicon and polyimide flexible substrates. Both thin films: In2O3 and a-Si were deposited by magnetron sputtering. Such heterostructure thin film systems are attractive because of their ability to convert solar energy into electrical one. Grown Heterostructures films were treated by simultaneous influence of an electron beam and high energetic photons with energy more than 1.5 eV in the so called vacuum photo-thermal processing (VPP).

Silicon samples of 100 Ω/sq and 45 Ω/sq were selected as substrates. Thin films deposition was done in argon atmosphere by DC magnetron sputtering.

It is shown that:

Open circuit voltage of the proposed structure may reach up to ~ 0.35 V,

Short circuit current was of no more then 10-7 A,

Polyimide materials may be used as substrates for PV thin film deposition structures,

VPP dramatically varies the photovoltaic properties of the heterostructure

Details

World Journal of Engineering, vol. 11 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 8 July 2021

Ahmad Sauffi Yusof, Zainuriah Hassan, Sidi Ould Saad Hamady, Sha Shiong Ng, Mohd Anas Ahmad, Way Foong Lim, Muhd Azi Che Seliman, Christyves Chevallier and Nicolas Fressengeas

The purpose of this paper is to investigate the effect of growth temperature on the evolution of indium incorporation and the growth process of InGaN/GaN heterostructures.

Abstract

Purpose

The purpose of this paper is to investigate the effect of growth temperature on the evolution of indium incorporation and the growth process of InGaN/GaN heterostructures.

Design/methodology/approach

To examine this effect, the InGaN/GaN heterostructures were grown using Taiyo Nippon Sanso Corporation metal-organic chemical vapor deposition (MOCVD) SR4000-HT system. The InGaN/GaN heterostructures were epitaxially grown on 3.4 µm undoped-GaN (ud-GaN) and GaN nucleation layer, respectively, over a commercial 2” c-plane flat sapphire substrate. The InGaN layers were grown at different temperature settings ranging from 860°C to 820°C in a step of 20°C. The details of structural, surface morphology and optical properties were investigated using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), atomic force microscopy and ultraviolet-visible (UV-Vis) spectrophotometer, respectively.

Findings

InGaN/GaN heterostructure with indium composition up to 10.9% has been successfully grown using the MOCVD technique without any phase separation detected within the sensitivity of the instrument. Indium compositions were estimated through simulation fitting of the XRD curve and calculation of Vegard’s law from UV-Vis measurement. The thickness of the structures was determined using the Swanepoel method and the FE-SEM cross-section image.

Originality/value

This paper report on the effect of MOCVD growth temperature on the growth process of InGaN/GaN heterostructure, which is of interest in solid-state lighting technology, especially in light-emitting diodes and solar cell application.

Details

Microelectronics International, vol. 38 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 19 July 2021

Ark Ifeanyi, Patrick Isherwood and Aminat Olawumi Abdul-Lateef

Even though copper–tungsten has shown signs of potentials, relatively little is currently known about its appropriateness for photovoltaic application. This paper aims to evaluate…

Abstract

Purpose

Even though copper–tungsten has shown signs of potentials, relatively little is currently known about its appropriateness for photovoltaic application. This paper aims to evaluate the suitability of copper-tungs oxides as photovoltaic absorbers while investigating the consequences of oxygen content variation.

Design/methodology/approach

Using profilometry, Hall measurements, Seebeck test and spectrophotometry, grown samples were defined. Samples of 5 standard cubic centimeters per minute (sccm) and 7 sccm exhibited appropriate characteristics and were further tested using personal computer one dimension (PC1D) computational simulation at the system stage. To grow materials with an average thickness below 0.45 µm, magnetron co-sputtering was used. Three sample sets, varied by oxygen flow rate, were made with flow rates of 5sccm, 7sccm and 9sccm, respectively.

Findings

Some samples proved to be effective absorbers, using a cadmium telluride device as the criterion of output calculation, with one sample chosen as ideal for each type of flow rate. For the chosen samples, an optimum thickness was also obtained, i. It was discovered that thinner cells, optimal for both groups with 0.6 µm, performed better to than other thicknesses.

Research limitations/implications

The material also demonstrated prospects for applications in window layers, but more needs to be known.

Practical implications

Thin film material properties and their operating processes are relatively complex, so it is important to find simple and cost-effective ways to forecast performance. While relatively new, numerical modeling has proven to be very useful in defining the critical properties of thin film devices, thereby helpful for predictions of performance. Solar cell capacitance simulator one dimension, amorphous semiconductor analysis, personal computer one dimension (PC1D), analysis of micro-electronic and photonic structures and automat for simulation for heterostructures (33) are several common models in the thin film industry. Due to its availability and relative ease of use, PC1D was used in this project.

Social implications

As the search for the balance among performance, cost, reliability and availability continue, more absorber components continue to evolve, notably from the chalcogenides. Because of their ability to absorb light, ternary transition metal chalcogenides are useful in the production of hydrogen and in the energy storage sector, as well as in the production of light-emitting diodes and solar photovoltaic (PV).

Originality/value

There are several methods for the manufacture of copper–tungsten alloys, but the process of combinatorial sputtering of magnetrons provides satisfactory results even for the manufacture of various other materials. Cu2WSe4, an excellent alternative to sputtering, is one of the very few copper–tungsten selenide materials tested, synthesized by hot simple injection to have strong crystallinity and lacks impurity. The optical properties of colloidal Cu2WSe4 show that Schottky diode–like behaviors are present in the material, suggesting its potential for use in solar cells. Cu-W alloys could have a lot more to give the PV industry, by all indications. Further exploration of the oxides by this work is thus justified. Transparent conducting oxides, interfacial layers or charge-transporting compounds are commonly used as transition metal oxides. Nevertheless, as absorbers, metal oxides such as BiFeO3 and the traditionally highly studied Cu2O have been tested, with Cu2O showing a conversion efficiency of up to 10% under particular conditions. This displays strong electronic and optical properties, so there might be some possibility of studying other PV absorption metal oxides. The optical properties of colloidal Cu2WSe4 show that Schottky diode–like behaviors are present in the material, suggesting its potential for use in solar cells.

Details

World Journal of Engineering, vol. 19 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 April 1993

E.F. Chor and C.J. Peng

A compound emitter heterojunction bipolar transistor (HBT) structure that incorporates an additional heterojunction within the emitter for minority carrier confinement has been…

Abstract

A compound emitter heterojunction bipolar transistor (HBT) structure that incorporates an additional heterojunction within the emitter for minority carrier confinement has been proposed. In this new device configuration, the single wide band‐gap emitter layer in a conventional HBT is replaced by two sub‐layers of wide band‐gap material, with the sub‐layer nearer the base having a narrower band‐gap. By means of numerical simulations, the compound emitter HBT was found to perform better than comparable conventional HBTs. With the AlGaAs(n) / GaAs heterostructure system, the optimum compound emitter HBT structure was found to be Al0.3Ga0.7As(n) ‐ Al0. 2Ga0.8As(n) / GaAs with grading at the two hetero‐interfaces. It has a low turn‐on voltage that is almost identical to that of a homojunction GaAs bipolar transistor with similar doping conditions. Compared with a conventional single emitter layer Al0.3Ga0.7As/GaAs HBT, the optimum compound emitter HBT has an enhancement in the current gain by approximately 2 folds, an improvement in the uniform current gain region from 2 to 4 decades of collector current density, and a slight increase in the unity‐gain cut‐off frequency fT by about 7 %.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 12 no. 4
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 2 October 2017

Evgeny L. Pankratov and Elena A. Bulaeva

The purpose of this paper is to analytically model redistribution of dopant in a heterostructure during annealing of dopant and/or radiation defects (during the modeling, the…

Abstract

Purpose

The purpose of this paper is to analytically model redistribution of dopant in a heterostructure during annealing of dopant and/or radiation defects (during the modeling, the authors consider two types of infusing of the dopant: dopant diffusion and ion implantation). The authors consider a heterostructure, which consists of a substrate and an epitaxial layer. After that the authors consider doping of several specific areas to manufacture heterodiodes and heterobipolar transistors framework hybrid cascaded multilevel inverter.

Design/methodology/approach

Based on the modeling, the authors introduce an approach to increase density of diodes and bipolar transistors framework hybrid cascaded multilevel inverter, which has been manufactured based on the heterostructure. The approach is based on using inhomogeneity of the heterostructure and optimization of annealing of dopant and/or radiation defects.

Findings

The approach gives us possibility to take into account nonlinearity of considered processes.

Originality/value

The authors introduce an analytical approach to model diffusion and ion types of doping with account concurrent changing of parameters in space and time.

Details

Multidiscipline Modeling in Materials and Structures, vol. 13 no. 4
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 1 July 2014

Matteo Porro, Carlo de Falco, Maurizio Verri, Guglielmo Lanzani and Riccardo Sacco

The purpose of this paper is to develop a computational model for the simulation of heterojunction organic photovoltaic devices with a specific application to a light harvesting…

Abstract

Purpose

The purpose of this paper is to develop a computational model for the simulation of heterojunction organic photovoltaic devices with a specific application to a light harvesting capacitor (LHC) consisting of a double layer of organic materials connected in series with two insulating layers and an external resistive load.

Design/methodology/approach

The model is based on a coupled system of nonlinear partial and ordinary differential equations describing current flow throughout the external resistive load as the result of exciton generation in the bulk, exciton dissociation into bonded pairs at the acceptor-donor material interface, and electron/hole charge generation and drift-diffusion transport in the two device materials.

Findings

Numerical simulation results are shown to be in good agreement with measured on-off transient currents and allow for novel insight on the microscopical phenomena which affect the external LHC performance, in particular, the widely different time scales at which such phenomena occur and their relation to the overall device dynamics.

Originality/value

The LHC demonstrates the viability of a novel approach for converting light energy into an electric current without a steady state flow of free charge carriers through the semiconducting layers. The new insight about the microscopic working principles that determine the macroscopically observed behavior of the LHC obtained via the model proposed in this paper are expected to serve as a basis for studying techniques for exploiting the full potential of the LHC.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 23 March 2012

Robert Bogue

The purpose of this paper is to review the technology and applications of solar‐powered sensors.

Abstract

Purpose

The purpose of this paper is to review the technology and applications of solar‐powered sensors.

Design/methodology/approach

Following a short introduction, this paper first considers photovoltaic technology and then describes a selection of solar‐powered sensors and their applications.

Findings

It is shown that solar‐powered sensors may be used as nodes in wireless sensor networks and also as stand‐alone devices. They offer a number of key operational and economic benefits and find applications in such diverse fields as structural and environmental monitoring, traffic management, weather forecasting, agriculture, process control, gas detection, satellite remote sensing and healthcare.

Originality/value

The paper illustrates the important role that solar‐powered sensors and systems play in a wide range of applications and industries.

Details

Sensor Review, vol. 32 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 14 August 2017

Evgeny L. Pankratov and Elena Alexeevna Bulaeva

The purpose of this paper is to analyze the redistribution of dopant and radiation defects to determine conditions which correspond to decreasing of elements in the considered…

Abstract

Purpose

The purpose of this paper is to analyze the redistribution of dopant and radiation defects to determine conditions which correspond to decreasing of elements in the considered inverter and at the same time to increase their density.

Design/methodology/approach

In this paper, the authors introduce an approach to increase integration rate of elements in a three-level inverter. The approach is based on decrease in the dimension of elements of the inverter (diodes and bipolar transistors) due to manufacturing of these elements by diffusion or ion implantation in a heterostructure with specific configuration and optimization of annealing of dopant and radiation defects.

Findings

The authors formulate recommendations to increase density of elements of the inverter with a decrease in their dimensions.

Practical implications

Optimization of manufacturing of integrated circuits and their elements.

Originality/value

The results of this paper are based on original analysis of transport of dopant with account transport and interaction of radiation defects.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 10 no. 3
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 4 January 2016

Mariya Petrova Aleksandrova

Purpose This study aims to apply the impedance spectroscopy (IS) for analyzing the electrical behavior and extracting the equivalent circuit of single-layer flexible organic…

Abstract

Purpose

Purpose This study aims to apply the impedance spectroscopy (IS) for analyzing the electrical behavior and extracting the equivalent circuit of single-layer flexible organic light-emitting diodes (OLEDs) with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) anode.

Design/methodology/approach

The preliminary ultraviolet (UV) treatment of the flexible substrate of polyethylene terephthalate (PET) influenced the conductivity of PEDOT:PSS anodes.

Findings

The IS showed that the OLED with UV-treated PET/PEDOT:PSS anodes had lower values of the contact resistance and higher value of the interface capacitance.

Originality/value

The obtained data were used for modeling of flexible OLEDs with polymeric anodes and calculation of important display parameters such as pixel refresh ratio, signal delays and energy losses due to contact resistances. These parameters were compared for PEDOT:PSS anodes deposited on PET treated and non-treated by UV.

Article
Publication date: 7 December 2020

Radha Sankararajan, Kirubaveni Savarimuthu, Sudha Murugesan, Kiruthika Ramany, Govindaraj Rajamanickam and Santhosh Narendhiran

The purpose of this paper is to fabricate an ethanol sensor which has bio-friendly and eco-friendly properties compared to the commercially available ethanol sensors.

219

Abstract

Purpose

The purpose of this paper is to fabricate an ethanol sensor which has bio-friendly and eco-friendly properties compared to the commercially available ethanol sensors.

Design/methodology/approach

This paper describes the construction of a highly sensitive ethanol sensor with low ppm level detection at room temperature by integrating three techniques. The first deals with the formation of organic/inorganic p-n heterojunction. Second, tuning of structural parameters such as length, diameter and density of Zinc Oxide (ZnO) nanostructure was achieved through introduction of the Fe dopant into a pure ZnO seed layer. Furthermore, ultra-violet (UV) light photoactivation approach was used for enhancing the sensing performance of the fabricated sensors. Four different sensors were fabricated by combing the above approaches. The structural, morphological, optical and material compositions were characterized using different characterization techniques. Sensing behavior of the fabricated sensors toward ethanol was experimented at room temperature with and without UV illumination combined with stability studies. It was observed that all the fabricated sensors showed enhanced sensing performance for 10 ppm of ethanol. In specific, FNZ (Fe-doped ZnO seeded Ni-doped Zn nanorods) sensor exhibited a higher response at 2.2 and 13.5 s for 5 ppm and 100 ppm of ethanol with UV light illumination at room temperature, respectively. The photoactivated FNZ sensor showed quick response and speedy recovery at 18 and 30 s, respectively, for 100 ppm ethanol.

Findings

In this study, the authors have experimentally analyzed the effect of Fe (in ZnO seed layer and ZnO NRs) and Ni (in ZnO NRs) dopants in the room temperature sensing performance (with and without UV light) of the fabricated ethanol sensors. Important sensing parameters like sensitivity, recovery and response time of all the fabricated sensors are reported.

Originality/value

The Fe doped ZnO seeded Ni doped Zn nanorods (FNZ sample) showed a higher response at 2.2 s and 13.5 s for very low 5 ppm and 10 ppm of ethanol at room temperature under UV light illumination when compared to the other fabricated sensors in this paper. Similarly, this sensor also had quick response (18 s) and speedy recovery (30 s) for 100 ppm ethanol.

Details

Circuit World, vol. 48 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

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