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Gas sensors based on metal oxide nanoparticles and their application for environmentally hazardous gases detection – a mini-review

Jońca Justyna, Sówka Izabela

Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej

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2023

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Nr 85

7—27

EN

Hazardous gases have adverse effects on living organisms and the environment. They can be classified into two categories, i.e. toxic gases (e.g. H2 S, SO2 , CO, NO2 , NO and NH3 ) and greenhouse gases (e.g. N2 O, CH4 and CO2 ). Moreover, their presence in confined areas may lead to fire accidents, cause serious health problems or even death. Therefore, monitoring of these substances with gas sensors allows assessing the quality of the atmosphere, helps avoiding accidents and saves lives. Metal oxide semiconductor gas sensors (MOS) are one of the most popular choices for these applications owing to their numerous advantages, i.e. high sensitivity, long lifetime and short response time. However, these devices have their limitations as well. They exhibit baseline drift, sensor poisoning and poor selectivity. Although much has been done in order to deal with those problems, the improvement of MOS sensors continues to attract researchers’ attention. The strict control of gas sensing materials preparation is one of the approaches that helps to improve MOS sensors performance. Nanomaterials have been found to be more suitable candidates for gas detection than materials designed at microscale. Moreover, it was found that the regular and ordered morphology of metal oxide nanostructures, their loading with noble metals, or the formation of heterojunctions can exert additional influence on the properties of these nanostructures and improve their gas sensing performance, which will be described in the following sections of this paper. Following a discussion of the operation principle of MOS sensors, a comprehensive review of the synthesis and application of metal oxide nanoparticles in the construction of the MOS sensors dedicated for environmentally hazardous gases is presented. The paper discusses also present issues and future research directions concerning application of nanotechnology for gas sensing.

PL

Niebezpieczne gazy mają niekorzystny wpływ na organizmy żywe i środowisko. Zaliczamy do nich gazy toksyczne (np. H2 S, SO2 , CO, NO2 , NO i NH3 ), gazy cieplarniane (np. N2 O, CH4 i CO2 ). Co więcej, ich obecność w zamkniętych pomieszczeniach może doprowadzić do pożarów, spowodować poważne problemy zdrowotne, a nawet doprowadzić do śmierci. Monitorowanie tych substancji za pomocą czujników gazowych może pomóc uniknąć wypadków i uratować życie. Półprzewodnikowe czujniki gazowe na bazie tlenków metalu (MOS) są jednymi z najpopularniejszych w tych zastosowaniach ze względu na swoje liczne zalety, takie jak wysoka czułość, długa żywotność i krótki czas odpowiedzi. Urządzenia te mają również swoje ograniczenia, tj. wykazują dryft odpowiedzi w czasie, mogą ulec dezaktywacji i charakteryzują się słabą selektywnością, dlatego nadal prowadzone są badania nad poprawą parametrów czujników MOS. Ścisła kontrola procesu przygotowania materiałów czułych jest jedną z metod pozwalających na poprawę wydajności czujników MOS. Stwierdzono, że nanomateriały są bardziej odpowiednie do wykrywania gazów niż ich odpowiedniki zaprojektowane w mikroskali. Stwierdzono również, że regularna i uporządkowana morfologia nanostruktur tlenków metali, pokrywanie ich nanocząstkami metali szlachetnych lub tworzenie heterozłączy może poprawiać skuteczność wykrywania gazów. W przedstawionej pracy dokonano przeglądu metod syntezy i zastosowania nanocząstek tlenków metali w konstrukcji czujników gazów niebezpiecznych dla środowiska. W artykule omówiono również aktualne problemy i przyszłe kierunki badań nad zastosowaniem nanotechnologii do detekcji gazów.

2

A simulation study of temperature effects on performance parameters of silicon heterojunction solar cells with different ITO/a-Si:H selective contacts

Balent Jošt, Topič Marko, Krč Janez

Opto-Electronics Review

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2022

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Vol. 30, No. 1

art. no. e140557

EN

Effects of temperature variation on the performance of silicon heterojunction solar cells are studied using opto-electrical simulations. It is shown that the low-temperature cell efficiency is determined by the fill factor, while at high temperatures it depends on the open-circuit voltage. Simulations revealed that the low-temperature drop in the fill factor is caused by poor tunnelling, in particular at the ITO/p-a-Si:H heterojunction. The authors link this drop in fill factor to a low maximum-power-point voltage and show how poor tunnelling is reflected in the charge redistribution determining the device voltage. The effect of the contact work function on temperature behaviour of efficiency by varying the electron affinity of ITO layers has been demonstrated. It was also demonstrated that increasing the electron affinity of ITO on the p-side minimises the work function mismatch, leading to significant improvements in efficiency, especially at low temperatures, while optimisation on the n-side results in maginal improvements over the entire temperature range. In addition to the cumulative effects of the temperature-dependent parameters, their individual contributions to the efficiency were also investigated. Moreover, it was presented that the thermal energy (kT) determines the efficiency temperature behaviour, while other parameters play only a minor role. This paper shows how temperature variations affect device performance parameters.

3

Determination of the band structure diagram of semiconductor heterostructures applied in photovoltaics

Bogaczewicz Rafał Antoni, Popko Ewa, Gwóźdź Katarzyna Renata

Optica Applicata

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2021

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Vol. 51, nr 1

135--145

EN

Recently it has been found that the heterostructures of n-ZnO/p-Si are promising photovoltaic alternatives to silicon homojunctions. It is well known that the energy band diagram of a heterostructure is crucial for the understanding of its operation. This paper analyzes the ZnO/p-Si heterostructure band by using free AMPS-1D computer program simulations. The obtained numerical results are compared with theoretical calculations based on the depletion region approximation model and the Poisson’s equation for electric potential. The results of the simulation are also compared with the experimental C-V characteristics of the test n-ZnO/p-Si heterostructure. The simulated C-V characteristics is qualitatively consistent with the experimental C-V curve, which confirms the correctness of the determined band diagram of the n-ZnO/p-Si heterostructure.

4

Comparison of electrical properties of CuO/n-Si contacts with Cu/n-Si

Özmenteş Reşit, Temirci Cabir

Materials Science Poland

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2020

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Vol. 38, No. 3

475--483

EN

In this study, CuO/n-Si/Al heterojunction contacts were fabricated by thermal evaporation technique. Electrical characteristics of the samples were investigated with the current-voltage (I-V), capacitance-voltage/frequency (C-V/f), and conductance-voltage (G/V) measurements at room temperature. Also, Cu/n-Si/Al Schottky contact was produced as a reference sample to investigate the electrical properties of the samples. The values of ideality factor (n), barrier height (φb) and series resistance (Rs) of the samples were calculated from the forward bias current-voltage (I-V) and reverse bias capacitance-voltage (C-V) characteristics. Also, for checking the consistency of the results, Cheung and Norde functions were used. The experimental result values of CuO/n-Si contact were compared with the values of the reference Cu/n-Si Schottky diode. It was observed that the values of the ideality factor and barrier height of the CuO/n-Si heterojunction were higher than those of the Cu/n-Si Schottky contact, while the series resistance was lower. Also, it has been observed that the value of capacitance decreased with increasing frequency and after a certain value of frequency it was almost constant. The ideality factor of CuO/n-Si/Al heterostructure is about 2.40 and so, it is not close to the ideal behavior.

5

Heterozłącza p-CuO/n-Si dla zastosowań fotowoltaicznych

Czerwosz Elżbieta, Biernacki Krzysztof, Wronka Halina, Kozłowski Mirosław, Diduszko Ryszard, Firek Piotr, Fetliński Bartosz

Elektronika : konstrukcje, technologie, zastosowania

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2019

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Vol. 60, nr 12

36--39

PL

W artykule został przedstawiony stan wiedzy na temat heterozłączy p-CuO/n-Si oraz ich zastosowań w fotowoltaice. Na tym tle zostały zaprezentowane wyniki naszych badań w dziedzinie technologii otrzymywania takich struktur, badań ich właściwości fizycznych metodami rentgenowskimi i elektronomikroskopowymi oraz badań ich właściwości fotowoltaicznych. Heterozłącza p-CuO/n-Si zostały otrzymane dzięki zastosowaniu nowej metody, opracowanej w naszym Instytucie (Łukasiewicz - ITR), polegającej na połączeniu metody PVD i metody utleniania termicznego. Szczegóły metody opisane są w artykule. Wyniki pomiarów fotoprądów pokazały, że opracowane struktury są odpowiednie do zastosowań fotowoltaicznych.

EN

The state-of-art in a field of p-CuO/n-Si heterojunctions and their application in photovoltaics is presented in this paper. On this background the results of our studies concerning technology of such structures preparation, their properties investigated with x-ray diffraction and electron-microscopy methods as well as their photovoltaic properties are shown. The p-CuO/n-Si heterojunctions were prepared by innovative method elaborated in our Institute (Łukasiewicz - ITR). This method connects PVD and thermal oxidation methods. Details of this method are described in the paper. The results of photovoltaic measurements exhibited that prepared p-CuO/n-Si heterojunctions are suitable for photovoltaic applications.

6

Characterization of CuO/n-Si heterojunction solar cells produced by thermal evaporation

Özmenteş R., Temirci C., Özkartal A., Ejderha K., Yildirim N.

Materials Science Poland

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2018

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Vol. 36, No. 4

668--674

EN

Copper(II) oxide (CuO) in powder form was evaporated thermally on the front surface of an n-Si (1 0 0) single crystal using a vacuum coating unit. Structural investigation of the deposited CuO film was made using X-ray difraction (XRD) and energy dispersive X-ray analysis (EDX) techniques. It was determined from the obtained results that the copper oxide films exhibited single-phase CuO properties in a monoclinic crystal structure. Transmittance measurement of the CuO film was performed by a UV-Vis spectrophotometer. Band gap energy of the film was determined as 1.74 eV under indirect band gap assumption. Current-voltage (I-V) measurements of the CuO/n-Si heterojunctions were performed under illumination and in the dark to reveal the photovoltaic and electrical properties of the produced samples. From the I-V measurements, it was revealed that the CuO/n-Si heterojunctions produced by thermal evaporation exibit excellent rectifying properties in dark and photovoltaic properties under illumination. Conversion efficiencies of the CuO/n-Si solar cells are comparable to those of CuO/n-Si produced by other methods described in the literature.

7

Area equivalent WKB Compact modeling approach for tunneling probability in Hetero-Junction TFETs including ambipolar behaviour

Horst Fabian, Farokhnejad Atieh, Darbandy Ghader, Iñíguez Benjamín, Kloes Alexander

International Journal of Microelectronics and Computer Science

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2018

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Vol. 9, nr 2

47--59

EN

This paper introduces an innovative modeling approach for calculating the band-to-band (B2B) tunneling probability in tunnel-field effect transistors (TFETs). The field of application is the usage in TFET compact models. Looking at a tunneling process in TFETs, carriers try to tunnel through an energy barrier which is defined by the device band diagram. The tunneling energy barrier is approximated by an approach which assumes an area equivalent (AE) triangular shaped energy profile. The simplified energy triangle is suitable to be used in the Wentzel-Kramers-Brillouin (WKB) approximation. Referring to the area instead of the electric field at individual points is shown to be a more robust approach in terms of numerical stability. The derived AE approach is implemented in an existing compact model for double-gate (DG) TFETs. In order to verify and show the numerical stability of this approach, modeling results are compared to TCAD Sentaurus simulation data for various sets of device parameters, whereby the simulations include both ON- and AMBIPOLAR-state of the TFET. In addition to the various device dimensions, the source material is also changed to demonstrate the feasibility of simulating hetero-junctions. Comparing the modeling approach with TCAD data shows a good match. Apart the limitations demonstrated and discussed in this paper, the main advantage of the AE approach is the simplicity and a better fit to TCAD data in comparison to the quasi-2D WKB approach.

8

Top PV market solar cells 2016

Płaczek-Popko E.

Opto-Electronics Review

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2017

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Vol. 25, No. 2

55--64

EN

Photovoltaic (PV) technologies which play a role in PV market are divided into basic two types: wafer-based (1st generation PV) and thin-film cell (2nd generation PV). To the first category belong mainly crystalline silicon (c-Si) cells (both mono- and multi-crystalline). In 2015 around 90% of the solar market belonged to crystalline silicon. To the 2nd generation solar cells belongs thin film amorphous silicon (a- Si) or a combination of amorphous and microcrystalline silicon (a-Si/µc-Si), compound semiconductor cadmium telluride (CdTe), compound semiconductor made of copper, indium, gallium and selenium (CIS or CIGS) and III–V materials. The PV market for thin film technology is dominated by CdTe and CIGS solar cells. Thin film solar cells’ share for all thin film technologies was only 10% in 2015. New emerging technologies, called 3rd generation solar cells, remain the subject of extensive R&D studies but have not been used in the PV market, so far. In this review the best laboratory 1st and 2nd generation solar cells that were recently achieved are described. The scheme of the layer structure and energy band diagrams will be analyzed in order to explain the boost of their efficiency with reference to the earlier standard designs.

9

CIS, CIGS and CIBS thin film solar cells and possibilities of their application in BIPV

Frydrychowicz-Jastrzębska G., Bugała A.

Computer Applications in Electrical Engineering

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2016

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Vol. 14

364--377

EN

Photovoltaic thin–film solar cells have gained more and more popularity in recent years. As well as high efficiency, they have a number of properties allowing their application in BIPV. The paper presents thin film copper indium diselenide cells (CuInSe2 – CIS) and their modifications. Their electric and optical properties are characterised. The subject of presentation includes phenomena, which take place in these solutions as well as issues related to selection of absorbing–generating layers and a window layer, including the possibilities of solving these issues to obtain high efficiency of photovoltaic conversion. At present, the photovoltaic conversion is already at the level of 22.3% in laboratory conditions [29]. The examples of roof and facade applications of CIS with regards to buildings are provided.

10

Si/ZnO nanorods with Ag nanoparticles/AZO heterostructures in PV applications

Gwóźdź K., Płaczek-Popko E., Gumienny Z., Zielony E., Pietruszka R., Witkowski B. S., Wachnicki Ł., Gierałtowska S., Godlewski M., Chang L. B.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2016

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Vol. 64, nr 3

529--533

EN

Our studies focus on test structures for photovoltaic applications based on zinc oxide nanorods grown using a low-temperature hydrothermal method on a p-type silicon substrate. The nanorods were covered with silver nanoparticles of two diameters – 20–30 nm and 50–60 nm – using a sputtering method. Scanning electron microscopy (SEM) micrographs showed that the deposited nanoparticles had the same diameters. The densities of the nanorods were obtained by means of atomic force microscope (AFM) images. SEM images and Raman spectroscopy confirmed the hexagonal wurtzite structure of the nanorods. Photoluminescence measurements proved the good quality of the samples. Afterwards an atomic layer deposition (ALD) method was used to grow ZnO:Al (AZO) layer on top of the nanorods as a transparent electrode and ohmic Au contacts were deposited onto the silicon substrate. For the solar cells prepared in that manner the current-voltage (I-V) characteristics before and after the illumination were measured and their basic performance parameters were determined. It was found that the spectral characteristics of a quantum efficiency exhibit an increase for short wavelengths and this behavior has been linked with the plasmonic effect.

11

Characterisation of a heterojunction structure based on Au doped WO3 and SnO2

Halek P., Teterycz H., Fiedot M., Wiśniewski K.

Elektronika : konstrukcje, technologie, zastosowania

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2011

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Vol. 52, nr 3

28-30

EN

The microstructure, the composition and DC behaviour of a heterojunction gas sensor formed between SnO2 and 0.8% Au doped WO3 were evaluated. The sensor was prepared by standard thick film technology. The single phase layers and the junction region show a porous structure. The electric measurements were performed in a wide range of temperatures and bias voltages in the rang from -1 to +1 V. The n-n heterojunction show a rectifying behaviour in temperatures from 200 to 400°C.

PL

W pracy przedstawiono wyniki badań heterozłączowego czujnika gazu na bazie trójtlenku wolframu domieszkowanego złotem i dwutlenku cyny. Analizowany czujnik został wykonany standardową techniką grubowarstwową. Badania mikrostruktury i składu chemicznego poszczególnych warstw oraz obszaru złącza wykazywały, że charakteryzują się one dużą porowatością. Pomiary metodą cyklicznej woltamperometrii w szerokim zakresie temperatur w zakresie napięcia polaryzacji od -1 do +1 V ujawniły, że złącze WO3 +Au/SnO2 posiada właściwości prostujące w zakresie temperatury od 200 do 400°C.

12

Characterization of laser ablated AgInSe2 films

Pathak D., Bedi R. K., Kaur D.

Materials Science Poland

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2010

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Vol. 28, No. 1

199--205

EN

AgInSe2 (AIS) thin films have been grown directly on silicon by means of a pulsed laser deposition technique. The X-ray diffraction studies show that the films are textured in the (112) direction. Increase of the substrate temperature results in a more ordered structure. Composition of the samples has been analysed by EDAX. It was found that the stoichiometry is better maintained with the PLD technique than with other traditional methods like thermal evaporation. The optical studies of the films show that the optical band gap is about 1.20 eV. The results of investigations may be of interest for a better understanding of the growth processes of chalcopyrite thin films on silicon materials.

13

Optical beam injection methods as a tool for analysis of semiconductor structures

Domaradzki J., Kaczmarek D.

Optica Applicata

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2005

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Vol. 35, nr 1

129-137

EN

Optical beam injection methods, such as an optical beam induced current (OBIC) one, have several advantages. Such methods enable a comprehesive analysis of photocuurent generated at the microregion of a semiconductor material or a device by focused light beam. In the paper, examples of applications of the OBIC method for: i) examination of the silicon p-i-n diodes used in a scanning electron microscope (SEM) as a detector and ii) localization of electrically active regions at the interface of the new transparent oxide semiconductor (TOS)-semiconductor structure have been outlined.

14

Planar junction formation in HgCdTe infrared detectors

Rutkowski J.

Opto-Electronics Review

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2004

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Vol. 12, No. 1

123--128

EN

This paper presents an overview of fundamental techniques for planar junction formation in HgCdTe infrared detectors. At the beginning, the evolution of HgCdTe photodiode performance is presented. Further considerations are restricted to modern methods of p-n junction formation, so the current state of the art of different types of HgCdTe photodiodes is presented. The comparison of theoretical and experimental results for planar HgCdTe photodiodes is finally described.

15

Multilayer strained Si/SiGe structures: fabrication problems, interface characteristics, and physical properties

Orlov L. K., Horvath Z. J., Ivina N. L., Vdovin V. I., Steinman E. A., Orlov M. L., Romanov Y. A.

Opto-Electronics Review

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2003

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Vol. 11, No. 2

169-174

EN

The objectives of this investigation are structural and physical characteristics of the n-Si1–xGex/n(p)-Si heterojunction under strong elastic deformation of Si1–xGex layers which gives rise to misfit dislocations in the heteroboundary region; the factors playing the main role in formation of the band structure of the system; the use of transmission electron microscopy and optical methods for determination of the phenomena connected with misfit dislocations in the grown epitaxial structure; the electrical characteristics of diode structures and the process of electron-hole recombination via dislocation states in a heterojunction.

16

Structural, optical and electrical characterization of Co-Pd doped TiO2 semiconducting thin films sputtered on silicon

Domaradzki J., Prociów E., Kaczmarek D., Berlicki T., Kudrawiec R., Misiewicz J., Mielcarek W.

Optica Applicata

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2003

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Vol. 33, nr 4

661-668

EN

The fundamental structural, electrical and optical properties of junction-based devices composed of semiconducting thin films of metal oxide on a semiconductor were examined. Thin films were deposited on silicon and silica substrates by hot target reactive magnetron sputtering process. During the deposition base TiO2 films were doped with Co, Pd transition metals. Electrical and optical beam induced current (OBIC) analysis confirmed the formation of a junction based on a semiconduting thin film of metal oxide–semiconductor interface

17

Zastosowanie laserów półprzewodnikowych w systemach telekomunikacji multimedialnej

Korzec Z., Kacprzak T.

Elektronika : prace naukowe

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2001

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nr 6

31-49

PL

Stały wzrost zapotrzebowania na przekazywanie informacji na dowolne odległości, w krótkim czasie, wymusza powstawanie nowych technik ich przetwarzania, wysyłania i odbioru. W ostatnich latach wykorzystanie najnowszych osiągnięć w dziedzinie technologii laserów półprzewodnikowych, w powiązaniu z liniami światłowodowymi i nowymi metodami zwielokrotniania w dziedzinie długości fal, pozwoliło na przenoszenie informacji w liniach światłowodowych zarówno na małe, średnie, jak i duże odległości z niemożliwą do zrealizowania w innych systemach prędkością - rzędu terabitów na sekundę. W artykule omówiony został rozwój laserów półprzewodnikowych i przedstawione zostały ich najnowsze rozwiązania technologiczne.

EN

Recently optical networks are growing at unprecedented rates to satisfy the urgent demands in data traffic, and an associated tremendous bandwidth request made by users, brought on by new telecommunication and multimedia services. Photonics, the technology of using particles of light as information carriers, takes the first place in the telecommunication systems because of the advantage of optical fiber over coper cable for data communication. Optical fibers are capable of carrying data at rates exceeding terabits per second at distances even of thousands of kilometers. Initially, as the main light source light emitty diode was mainly used. But now, as data rates increased, communication system make special demands on optical sources. The light source for optical data transmission must be small, efficient, capable of high speed modulation and must have controllable pattern of emissions in the optimum wavelength windows for silica fiber or in shorter-wavelength ranges for free-space interconnections. These requests can be fulfilled only by semiconductor injection laser. Nowadays this device can be manufactured inexpensively in large volumes and can easily interface with other circuitry, preferably silicon based. It can be diced either individually or in arrays that are easily coupled to optical fibers. This paper reviews recent progress in semiconductor lasers technology with emphasis on their application in optical telecommunication systems. Semiconductor injection lasers were first developed in 1962, but it was not until 1970 that a potentially practical device was demonstrated. The key moment in their development was the invention of the double heterostructure (DH- laser). The most important advantage of the DH laser is that it concentrates carriers in a very small region, thus a carrier density high enough to support laser oscillation can be achieved with a relatively low drive current. The next very important step is development of distributed-feedback laser and vertical-cavity, surface-emitting laser (VCSEL). These low-cost, nearly ideal sources are changing the attitudes tower modern optical communications.

18

Admittance measurements on CIGS solar cells

Kubiaczyk A., Nawrocka M., Igalson M.

Opto-Electronics Review

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2000

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Vol. 8, No. 4

378-381

EN

Thin film solar cells based on polycrystalline CIGS absorbers are one of the most promising candidates for the low-cost and efficient large-scale solar energy conversion devices. Electronic transport properties of ZnO/CdS/Cu(In,Ga)Se₂ solar cells were investigated by means of admittance measurements in a frequency range from 600 Hz to 1 MHz and a temperature range from 80 to 300 K. Dependent on the sample under investigation, one characteristic frequency (inflection point) corresponding to an activation energy between 80 and 160 meV or two points corresponding to an activation energy about 400 meV have been observed. Analysis of the measured frequencies and obtained activation energies provides information on the equilibrium Fermi level position at the CdS/CIGS interface.