Composition related electrical active defect states of InGaAs and GaAsN

This paper discusses results of electrically active defect states - deep energy level analysis in InGaAs and GaAsN undoped semiconductor structures grown for solar cell applications. Main attention is focused on composition and growth condition dependent impurities and the investigation of their possible origins. For this purpose a widely utilized spectroscopy method, Deep Level Transient Fourier Spectroscopy, was utilized. The most significant responses of each sample labelled as InG2, InG3 and NG1, NG2 were discussed in detail and confirmed by simulations and literature data. The presence of a possible dual conduction type and dual state defect complex, dependent on the In/N composition, is reported. Beneficial characteristics of specific indium and nitrogen concentrations capable of eliminating or reducing certain point defects and dislocations are stated

N coordination chemistry in diluted InGaAs nitride layers

GaAsN and InGaAsN semiconductor alloys with a small amount of nitrogen, so called dilute nitrides, constitute a novel compounds family with applications in telecom lasers and very efficient multijunction solar cells. The incorporation of N, which has a much larger electronegativity and smaller atomic size compared to As, induces a strong structural distortion in the InGaAs coordination chemistry, which will also affect the material electronic structure and band-gap. In particular, the nearest-neighbour bonding configuration of the N in InGaAsN has proven its influence on the band-gap. Our ARXPS results demonstrate that a higher growth temperature favour the formation of In-N bonds.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. - MINECO through TEC2011-28639-C02-02 and TEC2014-54260-C3-3-P - Wroclaw University of Technology statutory gran

AP-MOVPE Technology and Characterization of InGaAsN p-i-n Subcell for InGaAsN/GaAs Tandem Solar Cell

Tandem (two p-n junctions connected by tunnel junction) and multijunction solar cells (MJSCs) based on AIIIBV semiconductor compounds and alloys are the most effective photovoltaic devices. Record efficiency of the MJSCs exceeds 44% under concentrated sunlight. Individual subcells connected in series by tunnel junctions are crucial components of these devices. In this paper we present atmospheric pressure metal organic vapour phase epitaxy (AP-MOVPE) of InGaAsN based subcell for InGaAsN/GaAs tandem solar cell. The parameters of epitaxial structure (optical and electrical), fabrication process of the test solar cell devices and current-voltage (J-V) characteristics are presented and discussed

Collection of flint materials from Amiens from the collection of the Archaeological Museum in Krakow.

Praca prezentuje wyniki analizy zabytków krzemiennych ze stanowiska Amiens. Zostały one zebrane przez Albina Jurę oraz Krzysztofa Sobczyka w latach 50 i 70. XX wieku. W pierwszej kolejności poruszono problematykę formowania się oraz rozprzestrzenienia kultury aszelskiej w dolnym paleolicie. Następnie w oparciu o dane geologiczne podjęto próbę scharakteryzowania średniej terasy Sommy, skąd pozyskano artefakty. Inwentarz z Amiens składa się z 14 zabytków, z czego 7 określono jako aszelskie pięściaki. Precyzyjne wydatowanie opracowanego materiału jest utrudnione ze względu na brak zadokumentowanego kontekstu stratygraficznego. Podczas analizy skupiono się obserwacji zastosowanych technik krzemieniarskich.The work presents the results of the analysis of flint monuments from the Amiens site. They were collected by Albin Jura and Krzysztof Sobczyk in the 1950s and 1970s. The problems of the formation and spreading of Acheulean culture in the Lower Paleolithic were raised first. Next, based on geological data, an attempt was made to characterize the average Somme terrace, from which the artifacts were obtained. The Amiens inventory consists of 14 monuments, 7 of which were referred to as the Acheulean handaxes. Precise spending of the developed material is difficult due to the lack of a documented stratigraphic context. During the analysis, the observations of the flint techniques applied were focused

Collocability to the verb in Richard Wagner's opera "The Valkyrie"

Głównym celem niniejszej pracy magisterskiej pt. Zur Kollokabilität des Verbs in Richard Wagners Oper „Die Walküre“ była charakterystyka pojęcia kolokacji, a następnie kolokacji czasownikowych w operze Richarda Wagnera pt. Die Walküre. Poszczególne rozdziały, mianowicie część teoretyczna niniejszej pracy, dają zatem odpowiedź na pytania, czym są kolokacje, jak są klasyfikowane, jak również jakie problemy mogą występować przy tłumaczeniu kolokacji. Aby osiągnąć założony cel, przeprowadzona została klasyfikacja kolokacji czasownikowych, przedstawiona w części praktycznej pracy. Kolokacje czasownikowe z opery Die Walküre zostały klasyfikowane pod kątem struktury. Stwierdzono, które typy kolokacji występują najczęściej w operze Wagnera. Utworzono listę 220 kolokacji czasownikowych. Kolokacje zostały następująco sklasyfikowane i poddane analizie: czasownik + rzeczownik, czasownik + czasownik, czasownik + przymiotnik, czasownik + przysłówek. Celem badania było ukazanie, które czasowniki tworzą największy potencjał kolokacyjny.The main objective of this thesis Collocability to the verb in Richard Wagners opera "The Valkyrie" was to characterize the concept of collocation, collocation and verb in the opera by Richard Wagner The Valkyre. Individual chapters, namely, the theoretical part of this work, therefore, give the answer to the question, what are collocations like are classified, as well as what problems may occur when translating collocations. To achieve this goal, the classification was carried out verbal collocations presented in the practical work. Verb collocations from the opera The Valkyrie were classified in terms of structure. found that collocation types are most common in Wagner's opera. created a list of 220 verbal collocations. Collocations were classified as follows and analyzed: verb + noun, verb + verb, verb + adjective, verb + adverb. aim of this study was to show that words have the greatest collocations potential.Das Hauptziel der vorliegenden Magisterarbeit unter dem Titel: Zur Kollokabilität des Verbs in Richard Wagners Oper „Die Walküre“ war, die Charakteristik des Begriffs der Kollokation und der verbalen Kollokationen aus dem Bereich der Richard Wagners Oper Die Walküre darzustellen. Die einzelnen Kapiteln, also der theoretische Teil dieser Arbeit, geben die Antwort, was Kollokationen sind, wie sie klassifiziert werden und auch welche Probleme bei der Übersetzung von Kollokationen auftreten können. Um das Ziel zu erreichen, wurde die Klassifikation der verbalen Kollokationen durchgesucht, die in dem analytischen Teil der Arbeit dargestellt wurde. Die verbalen Kollokationen aus der Oper Die Walküre wurden nach der Struktur klassifiziert. Es wurde festgestellt, welche Kollokationstypen am häufigsten in Wagners Oper auftreten. Zuerst wurde die Menge von Kollokationen gebildet, die 220 verbalen Kollokationen umfasst. Demnächst wurden diese Kollokationen wie folgt klassifiziert und analysiert: Verb + Substantiv, Verb + Verb, Verb + Adjektiv, Verb + Adverb. Das Ziel der Untersuchung war die Vorlegung, welche Verben die größten Kollokationspotentiale bilden

Comparison of the Efficiency of Two Types of Heat Exchangers with Parallel Plates Made of Varied Materials

The paper discusses two mathematical models for the air flow through a plate heat exchanger with parallel plates. The first exhausts the used air and then supplies the fresh air. The second exhausts the used air above the plate and simultaneously supplies fresh air under it (counter-flow exchanger). In both cases, the exhaust air heat is used to heat the supply air. The purpose of the research is to verify which exchanger uses the exhaust air heat more efficiently. The method of the Trefftz function was used to determine approximate solutions of the analysed problems. The results obtained for 1.2 mm thick steel, aluminium, and copper plates and for external winter, summer, and spring–autumn temperatures are discussed. The results indicate that steel is the best material for a plate heat exchanger, and the counter-flow exchanger is more efficient of the two. Thanks to the use of thin steel plates and the reduction of the air exchange time to a few minutes, cheap and efficient counter-flow exchangers can be obtained

Comparison of the Efficiency of Cross-Flow Plate Heat Exchangers Made of Varied Materials

This paper discusses a mathematical model for airflow through a cross-flow plate heat exchanger. The exhaust air is used to heat the supply air. Three kinds of plates are considered: made of aluminium, copper, and steel. The purpose of this research was to verify which material used to build the plate heat exchangers uses the exhaust air heat more efficiently. The method of the Trefftz function was used to determine approximate solutions to the analysed problem. The results obtained for 1.2 mm-thick plates and for external winter, summer, and spring–autumn temperatures are discussed. The results indicate that if the efficiency and price of the metals are considered, then steel is the best material for the plate heat exchanger. Thanks to the use of thin steel plates and the reduction in air exchange time to a few minutes, a cheap and efficient cross-flow heat exchanger can be obtained

Photoluminescence and Raman spectroscopies as an optical approach of stress determining in MOVPE grown quantum cascade laser structures

In the presented work, an optical approach of stress determining in metalorganic vapor phase epitaxy (MOVPE) grown quantum cascade laser (QCL) structures was reported. In the case of such sophisticated structures containing hundreds of thin layers, it is important to minimize the stress generated in the QCL core. Techniques enabling determination of stress in such thin layers as those described in the article are photoluminescence and Raman spectroscopies. Based on Raman shift or changes in photoluminescence signal, it is possible to analyze stress occurring in the structure

Role of nitrogen in carrier confinement potential engineering and optical properties of GaAs-based quantum wells heterostructures

In this work, the authors present the results of optical characterization of GaAs-based multiple quantum well heterostructures, together with energy band structure analysis. The optical properties were investigated by applying photoluminescence spectroscopy. Structures with GaInNAs, GaInAs and GaNAs multiple quantum wells emitting around 1 μm, grown by atmospheric pressure metalorganic vapor phase epitaxy, were compared in this work. The role of nitrogen in quantum well carriers confinement potential was analysed. The photoluminescence intensities of the samples were correlated with the analysis of energy band structures and the overlaps of the carriers’ wave functions. In addition, the main carrier activation energies were estimated based on photoluminescence temperature dependence and the Arrhenius plots analysis. It was deduced that the thermal photoluminescence decay is most probably related to the escape of electrons whereas the holes, independently of the potential well depth, are additionally confined by the local inhomogeneities or by the Coulomb interaction with the confined electrons

The influence of quantum well and barrier thicknesses on photoluminescence spectra of InGaAs/AlInAs superlattices grown by LP-MOVPE

In the presented work, the influence of the quantum well and barrier thicknesses on optical characteristics of InGaAs/AlInAs superlattices was reported. Six different structures of In0.53Ga0.47As/Al0.48In0.52As superlattices lattice-matched to InP were grown by low pressure metal organic vapour phase epitaxy (LP-MOVPE). Optical properties of the obtained structures were examined by means of photoluminescence spectroscopy. This technique allows quick, simple and non-destructive measurements of radiative optical transitions in different semiconductor heterostructures.The analysis of recorded photoluminescence spectra revealed the influence of the quantum well and barrier thicknesses on the emission line energy