CELULE FOTOVOLTAICE CU HETEROJONCȚIUNEA n+CdS-po-p+InP: APLICĂRI TEHNOLOGICE, METODE ŞI REZULTATE ALE CERCETĂRILOR

Au fost obținute celule fotovoltaice (CF) cu heterojoncțiunea nCdS-pInP și strat intermediar epitaxial poInP, fiind cercetate proprietățile lor electrice și fotoelectrice. Grosimile straturilor pInP și al celui frontal nCdS au variat respectiv în intervalul 2,7...6,2 – 0,9...3,6 µm în dependență de durata de depunere. S-a constatat că parametrii fotoelectrici au valorile maximale pentru grosimile de 4,5...5 µm pentru stratul poInP și de 0,9 µm pentru stratul nCdS, eficiența maxi­mală a CF cu structura n+CdS-po-p+InP fiind de 14,6% (100 mW×cm-2).PHOTOVOLTAIC CELLS WITH n+CdS-po-p+InP HETEROJUNCTION:  TEHNOLOGICAL APPLICATIONS, METHODS AND RESEARCH RESULTSPhotovoltaic cells (PVC) with nCdS-pInP heterojunction and an intermediate poInP epitaxial layer were obtained and their electrical and photoelectric properties were investigated. The thicknesses of the pInP layer and of the nCdS frontal layer varied in the range of 2.7 to 6.2 μm and 0.9 to 3.6 μm respectively, depending on the deposition time. It was found that photoelectric parameters have maximum values when the thickness of poInP layer is of 4.5 ... 5 μm and for nCdS layer is of 0.9 μm, the maximum efficiency of PCV with the structure n+CdS-po-p+InP was of 14.6% (100 mW×cm-2).</p

ZINC OXIDE THIN FILMS PREPARED BY SPRAY PYROLYSIS TECHNIQUIE IN ARGON FLOW

ZnO thin layers were grown from zinc acetate dissolved in methanol-acetic acid-water solution with the molarity of 0.2M by using the pulverization method in an argon flow at the temperatures of 250-450°C. The temperature dependence of electrical and optical properties of the obtained layers were studied. The optical transmittance at the wavelengths of (300 -1000) nm has the values of 80-85%. The resistivity of ZnO thin layers grown at 450°C decreases from 33W•cm to       0,028 W•cm after annealing in hydrogen at 450°C during an hour. The radiative recombination is related to the electron transitions to the deep levels and band to band transitions at the charge carriers transitions with the LO type phonons.</p

Toward a construct of dynamic capabilities malfunction: Insights from failed Chinese entrepreneurs

This paper explores the processes and mechanisms of business failure in emerging economies. Drawing from the experiences of 50 failed entrepreneurs in China, we developed the concept of dynamic capabilities malfunction (DCM) to explain how business failure can stem from maladaptive, misallocation of attention and internal deficiencies. Our phase model explicates how exogenous and endogenous factors can interplay to contribute to DCM that ultimately led to the business closures. Another unexpected finding was that the failure occurred during the process of business transition. The implications for business failure research in emerging markets are discussed

Europeanization of juvenile criminal law : the example of Turkey

Le Conseil de l'Europe -créé à la suite de la Seconde Guerre mondiale afin de reconstruire un espace démocratique et juridique commun -dont les travaux sur le droit pénal des mineurs sont issus des évolutions nationales entamées au début du XXe siècle, s'attacha à valoriser l'expérience des juridictions spécialisées existantes dans quelques pays européens et grâce auxquelles les mineurs commençaient à faire l'objet d'un traitement différencié de celui des adultes. Depuis, observant les préoccupations des États membres à l'égard de la délinquance juvénile et les contours changeants de leurs politiques pénales, le Comité des Ministres du Conseil de l'Europe élabore, au moyen de recherches criminologiques et comparatives, de colloques et de conférences, des recommandations et lignes directrices conduisant à l'harmonisation des droits nationaux autour de principes directeurs. Mue par son engagement dans l'européanisation du droit pénal des mineurs, la Cour européenne des droits de l'homme intégra les instruments internationaux et européens pertinents dans sa jurisprudence. Ce qui prend un caractère primordial dans les pays où l'application de la Convention est problématique et les violations des droits de l'homme récurrentes, parmi lesquels la Turquie. En conséquence, et malgré les modifications apportées dans la législation turque depuis 2005, nous ferons apparaître dans cette étude que ce membre du Conseil de l'Europe méconnaît encore l'autonomie de l'enfant, promeut toujours la punition en modèle éducatif, use régulièrement de la détention, et appréhende finalement de manière balbutiante la primauté de l'éducation sur la répression prônée par les principes directeurs.The work by the Council of Europe -founded following the Second World War to rebuild a common democratic and legal order-in the field of juvenile justice has been influenced by the national developments emerged in the early twentieth century and has been focusing on enhancing the experiences of the existing special judicial bodies in some European countries of which were established for distinguishing the treatment of juvenile delinquent from adults. Since then, the Comrnittee of Ministers of the Council of Europe, which observes the concerns of the member states on juvenile delinquency as well as their changing criminal justice policies, adopts recommendations and guidelines in order to establish guiding principles leading to harmonization of the national systems through organizing meetings, conferences and conducting comparative research on criminology. Similarly, the European Court of Human Rights (ECHR) gives reference to the relevant international and European instruments in its jurisprudence so as to contribute to the Europeanisation of juvenile justice. This becomes especially important in countries like Turkey-where the implementation of the ECHR is problematic and human rights violations are recurring. Consequently, this study shows that despite the legislative changes made since 2005, Turkey, which is a member of the Council of Europe, still ignores the autonomy of the child, promotes punishment like an educational method, resort to detention as a regular measure, and finally displays an reluctant and abstaining attitude in giving priority to education over punishment as established by the guidelines

INFLUIENŢA TRATĂRII TERMICE ÎN AZOT SAU ÎN VID ASUPRA PROPRIETĂŢILOR STRATURILOR DE GaN CRESCUTE PE Si(111) PRIN METODA HVPE

A fost studiată influenţa tratării termice la temperaturi ridicate în azot sau în vid asupra proprietăţilor stra­turilor de GaN depuse pe siliciu prin metoda reacţiilor chimice de transport în sistemul (H2-NH3-HCl-Ga-Al), (HVPE). În spec­trele de fotoluminescenţă (FL), la 300 K, ale straturilor netratate se evidenţiază două fâşii de recombinare radiantă, cu maximele la 370 şi 555 nm. La tratarea în azot intensitatea fâşiei 370 nm creşte, iar la tratarea în vid – descreşte. Inten­sitatea benzii galbene (555 nm), la tratare în ambele medii, scade neesenţial. Se demonstrează că parametrii electrici ai straturilor pot fi, de asemenea, modificaţi prin metoda tratării termice în azot sau în vid, precum şi prin durata de tratare. The influence of high temperature annealing in nitrogen or vacuum on properties of GaN layers deposited on Si(111) by HVPE mehodThe influence of high temperature annealing in nitrogen and vacuum of GaN layers deposited by chemical reactions transport (HVPE) in (H2-NH3-HCl-Ga-Al) system on their properties was studied. In the photo­luminescence (PL) spectra at 300 K of the untreated layers two recombination radiation bands with the plats at 370 nm and 555 nm were revealed. At the layers heat treatment the intensity of the radiation band at 370 nm increases when at the intensity of the yellow band (555 nm) decreases not significantly at the treatment in the both ambiances. It was shown that the electrical parameters could as well be controlled by using heat treatment in nitrogen and vacuum and this depends on the annealing duration. </p

CERCETAREA CAPACITĂȚII ȘI CONDUCTIBILITĂȚII ELECTRICE ALE JONCȚIUNILOR DIN P-INP

Au fost studiate caracteristicile capacitate-tensiune-conductabilitate-frecvenţă ale homo­joncţi­uni­lor n+-p°-p+InP cu şi fără strat frontal n+CdS obţinute cu aplicarea tehnologiilor din faza gazoasă în sistemul In-PCl3-H2 şi în volum cvasiînchis. S-a stabilit că distribuirea impurităţilor în regiunea sarcinii de baraj în astfel de joncţiuni este cu gradient liniar, iar la frecvenţele de 7…10 MHz impendanţa structurii este determinată de rezistenţa inductivă. Concentraţia stărilor super­ficiale pentru structurile n+-p°-p+InP cu strat frontal de n+CdS este cu un ordin mai mică decât fără acest strat, ceea ce va spori eficienţa CF obţinute în baza lor.CAPACITANCE AND ELECTRICAL CONDUCTIVITY STUDIES OF P-INP JUNCTIONSThe capacitance –voltage-conductivity-frequency dependencies of n+-po-p+InP with and without n+CdS frontal  layer, obtained  by using of gaseous phase epitaxial technology in a In-PCl3-H2 system and deposition in a quasi-closed volume, were studied. It was established that the impurity distribution in the space charge region of such junctions is of a linear gradient, and at the frequencies of 7…10 MHz the structure impedance is determined by the inductance resistance. The surface state concentration in n+-po-p+InP structures with the n+CdS frontal  layer is by an order of magnitude lower than in the same structures without it, which can enhance the efficiency of solar cells based on them.</p

CELULE FOTOVOLTAICE CU HETEROJONCŢIUNEA nCdS-pInP

Au fost studiate proprietăţile electrice şi fotoelectrice ale heterojoncţiunilor nCdS-pInP cu şi fără strat epitaxial inter-mediar poInP. S-a stabilit că la polarizări directe în mecanismul de transport al curentului predomină procesele de recom-binare în regiunea de sarcină spaţială. La polarizări inverse predomină procesele de tunelare. Prezenţa stratului epitaxial poInP depus repetat măreşte ISC până la 28,2 mA·cm-2, UCD până la 0,780 V, iar eficienţa conversiei energiei până la 15% la 300 K şi iluminare 100 mW/cm2. Fotosensibilitatea CF nCdS-poInP-pInP corespunde intervalului λ=550...950 nm cu un maximum plat localizat în intervalul λ=700...850 nm.HETEROJONCTION nCdS–pInP FOTOVOLTAIC CELLSElectrical and photoelectrical properties of nCdS-pInP hetero-junctions with and without intermediate poInP epitaxial layer were studied. It was established that the current flow mechanism at direct biases is determined mainly by the recombi-nation processes in the space charge region of the junction. At the reverse biases the tunneling processes are predominant. The presence of poInP layer leads to the photo-electrical parameters enhancing of hetero-junction: short circuit current increases up to 28,2 mA·cm -2, open circuit voltage up to 0,780V and the efficiency of solar energy conversion up to 15 % (at 300 K and illumination of 100mw/cm2). The photo-sensitivity of nCdS- poInP -pInP is in the wavelength region of λ= 550-950nm with a maximum localized to λ=700-850nm.</p