Wyniki wyszukiwania - BazTech

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Determination of electrical and thermal parameters of vertical-cavity surface-emitting lasers

Śpiewak Patrycja, Gębski Marcin, Strupiński Włodek, Czyszanowski Tomasz, Kołkowski Walery, Pasternak Iwona, Sarzała Robert P., Nakwaski Włodzimierz, Wasiak Michał

Metrology and Measurement Systems

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2023

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Vol. 30, nr 3

519--529

EN

Experimental methods are presented for determining the thermal resistance of vertical-cavity surface-emitting lasers (VCSELs) and the lateral electrical conductivity of their p-type semiconductor layers. A VCSEL structure was manufactured from III-As compounds on a gallium arsenide substrate. Conductivity was determined using transmission line measurement (TLM). Electrical and thermal parameters were determined for various ambient temperatures. The results could be used for computer analysis of VCSELs.

2

The role of quantum-well states and carrier scattering times in discontinuities of opto-electrical characteristics of SCH lasers

Kozioł Z, Matukhin S I, Buduleva E A

Optica Applicata

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2014

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Vol. 44, nr 1

135--146

EN

Drift-diffusion computer simulation model available in Synopsys’ Sentaurus TCAD User Guide is used to study electrical and optical characteristics of a separate-confinement heterostructure laser based on AlGaAs. We investigate the role of the width and depth of quantum-well active region, below and above the lasing threshold. The device properties depend on both, the number of bound quantum-well states and on closeness of the highest bound states to conduction or valence band offset. The lasing action may not exist at certain widths or depths of quantum-well, and the threshold current is a discontinuous function of these parameters, at such values of quantum-well width or depth when the highest quantum-well bound states cross conduction or valence band energy offset. The effects are more pronounced at low temperatures. Discontinuities in characteristics are found, at certain conditions, in temperature dependences as well. The carriers scattering time on quantum-well is shown to have a crucial role for the amplitude of discontinuities of these characteristics. The current below the lasing threshold and the threshold current density itself decrease with an increase of quantum-well scattering times and the amplitude of discontinuities decreases then as well.

3

Reverse engineering of AlxGa₁₋xAs/GaAs structures composition by reflectance spectroscopy

Wośko M., Paszkiewicz B., Tarnowski K., Ściana B., Radziewicz D., Salejda W., Paszkiewicz R., Tłaczała M.

Opto-Electronics Review

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2011

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Vol. 19, No. 4

418-424

EN

The paper presents the application of non-modulation reflectance method for composition profiling of epitaxial AlxGa₁₋xAs/GaAs structures. This non-destructive method is based on spectral measurements and theoretical reflectance spectrum matching. This is a very accurate and sensitive method of determining the Al composition in AlxGa₁₋xAs layers and structures with resolution down to 1 nm. In this work, the authors describe theoretic principles of this method and present experimental results of characterization of different AlGaAs structures to prove the potential of the worked out method.

4

The role of photoluminescence excitation spectroscopy in investigation of quantum cascade lasers properties

Wójcik-Jedlińska A., Gradkowski K., Kosiel K., Bugajski M.

Electron Technology : Internet Journal

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2005/2006

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Vol.37/38, nr 10

1-4

EN

The properties of quantum cascade laser (QCL) structures have been investigated by optical technique based on spontaneous emission measurements: photoluminescence excitation (PLE) spectroscopy. Three types of test structures used for obtaining final QCL device were examined , i.e., single sequence of coupled quantum wells, which form an active region of the device, 30 sequences of this active region separated by 25 nm thick AlGaAs barriers and finally complete, undoped structure consisting of 30 of sequences repeated active regions and superlattice injectors. The results has been compared with numerical simulations. The role of such measurements has also been discussed.

5

Optimization of multi quantum well solar cell

Prażmowska J., Korbutowicz R.

Optica Applicata

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2005

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Vol. 35, nr 3

619-626

EN

Quantum well solar cell with GaAs wells and AlxGa1-xAs barriers was optimized. Particular emphasis was placed on enhancing the efficiency. Open-circuit voltage, short-circuit current density, fill factor have been also optimized. Many simulations of various structures were carried out. The conversion efficiency exceeding 27% was obtained. The algorithm of structures optimization that gives comprehensive information about solar cells parameters in a short time was shown. Spectral characteristics, efficiency of energy conversion as a function of light concentration, temperature and the geometrical and materials parameters of the solar cells structures were determined. These results are compared with nearly identical p-i-n solar cells: i) the first with /-region made from undoped GaAs (well material) and ii) the second with /-region from A0.1Ga0.9As (barrier material).

6

Advances in MOCVD technology for research, development and mass production of compound semiconductor devices

Christiansen K., Luenenbuerger M., Schineller B., Heuken M., Juergensen H.

Opto-Electronics Review

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2002

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Vol. 10, No. 4

237-242

EN

The recent years have seen a continuous transfer of exciting new technologies from basic research institutions to high yield mass production and into our everyday lives. Devices made from novel semiconductor compounds can be found in products ranging from consumer electronics to high speed backbone communication networks. This includes high power infrared laser diodes for glass fiber applications, ultra-high brightness light emitting diodes for display and lighting, high power blue and UV laser diodes for mass storage as well as all types of transistors made from silicon, III-V compounds and silicon-carbide. To facilitate the easy and straigtforward transfer from research scale experimental setups to large area substrates for mass production AIXTRON offers the whole scale of epitaxy solutions from single wafer systems to large scale production machines for up to 95 wafers. The easy configurability of the systems in terms of up-scaling of wafer sizes up to 7x6 inch for phosphides and arsenides and up to 84 inch for nitride materials in concurrence with easy maintenance, high reproducibility and high uniformity across the wafer and from wafer to wafer make the AIXTRON systems the ideal solution for mass production. The growth principle common to all AIXTRON MOCVD systems allows the easy up-scaling of established processes to larger configurations, even from single wafer AIX 200 systems to production type Planetary Reactors®. Add-ons like in-situ monitoring of the growth process by reflectometry (EpiTune® I and EpiTune® II) or Reflectance Anisotropy Spectroscopy (Epi-RAS®) help in a considerable reduction of the development time and costs, hence improving innovation cycles and the time-to-market of novel devices since the growth of the material can be monitored in real time.