id,collection,dc.contributor.author,dc.contributor.firstReferee,dc.contributor.furtherReferee,dc.contributor.gender,dc.date.accepted,dc.date.accessioned,dc.date.available,dc.date.embargoEnd,dc.date.issued,dc.description,dc.description.abstract[de],dc.identifier.uri,dc.identifier.urn,dc.language,dc.rights.uri,dc.subject,dc.subject.ddc,dc.title,dc.title.translated[de],dc.type,dcterms.accessRights.dnb,dcterms.accessRights.openaire,dcterms.format[de],refubium.affiliation[de],refubium.mycore.derivateId,refubium.mycore.fudocsId,refubium.mycore.transfer "a8cd9e39-53b1-4382-9991-47a87a41be44","fub188/14","Doka Yamigno, Serge","Prof. Dr. M.Ch. Lux-Steiner","Prof. W.D. Brewer PhD","n","2006-10-30","2018-06-07T16:18:24Z","2007-10-01T00:00:00.649Z","2007-10-02","2007","Title Zusammenfassung Table of contents Introduction 1 1\. Fundamental of CuGaSe2 5 1.1 Relevance of chalcopyrite thin films for solar cells 5 1.2 Structural properties of CuGaSe2 6 1.3 Electrical and optical properties of CuGaSe2 based devices 12 2\. Review of experimental methods 16 2.1 Photoluminescence Spectroscopy (PL) 16 2.2 Electron Spin resonance 20 2.3 XRD 22 2.4 ERDA 23 2.5 SNMS 23 3\. Deposition technology: Chemical closed- space vapor transport CCSVT 24 3.1 Chemical closed- space vapor transport (CCSVT) 24 3.2 Influence of the growth conditions on the CuGaSe2 film properties 31 3.3 Concluding remarks 35 4\. Optical and Structural properties of CCSVT- grown CuGaSe2 thin films 36 4.1 Absorption coefficient and optical band gap 36 4.2 Microstructural analysis 39 4.3 Elemental depth profiles in CuGaSe2 thin films 42 4.4 Concluding remarks 44 5\. Photoluminescence of as- prepared and intentionally Ge- implanted CuGaSe2 45 5.1 Ge- implantation and annealing process of CuGaSe2 46 5.2 Depth profiling of Ge in CuGaSe2 by SNMS 48 5.3 Photoluminescence of CCSVT as prepared CuGaSe2 thin films 49 5.4 Effects of Ge- Implantation on the Photoluminescence of CuGaSe2 thin films 58 5.5 Concluding remarks 67 6\. Electron spin resonance of as- grown and Ge- implanted CuGaSe2 thin films 69 6.1 Experimental details 69 6.2 Paramagnetic centers in as- grown and Ge- implanted CuGaSe2 thin films 69 6.3 Curie Paramagnetism of Ge- implanted CuGaSe2 thin films 72 6.4 Determination of spin concentration 74 6.5 Concluding remarks 75 7\. Summary and Outlook 77 7.1 Summary 77 7.2 Suggestions for future investigations 78 Appendix 79 Bibliography 86 Publications 93 Acknowledgements","A novel chemical closed- space vapor transport (CCSVT) technique has been developed for the growth of single phase CuGaSe2 thin films using two growth stages. The Ga2Se3 employed as source material was stoichiometrically volatilized at 550°C by a controlled amount of HCl/H2 agent at a fixed pressure. Cu precursors deposited on clean or Mo- coated soda lime glass (SLG) substrates were thermally and chemically treated under gaseous GaClx/H2Se atmosphere in the CCSVT cell. Cu deposited on the SLG substrate reacts with the volatilized gas phase compounds of Ga2Se3 and CuGaSe2 films were prepared with a growth rate of 230 - 240 nm/min by using a single stage process. After the first growth stage the major hurdle encountered is that no correlation between CuGaSe2 films properties (thickness and composition) could be realized because of their non- reproducibility for the same growth parameters. In order to overcome this hurdle, an additional second stage process was applied with a growth rate spanning 10 to 60 nm/min, for the fine tuning of the CuGaSe2 composition and electronic properties. Therefore, a film property- growth parameters relationship was found. \- Single phase polycrystalline thin films of CuGaSe2 in the compositional range of 1.0 ≤ [Ga]/[Cu] ≤ 1.3, corresponding to a thickness ranging from 1.6 μm to 1.9 μm deposited onto plain or Mo- coated soda lime glass (SLG) were prepared and found to be polycrystalline with a strongly preferred <221> orientation. A combination of microstructural investigations of the films by TEM, EDX within the TEM and ERDA measurements has shown that CuGaSe2 thin films possess high crystalline bulk quality with Cu, Ga and Se homogeneously distributed within the CuGaSe2 bulk. One of the main result of this present work was found to be the accumulation of Ga in the region of the CuGaSe2/Mo interface and the dependence of the CuGaSe2 surface composition on the integral [Ga]/[Cu] ratio in the film, namely Ga- and Cu- poor, Se- rich surface for stoichiometric films; and Cu- poor, and Ga- and Se- rich surface for increasing [Ga]/[Cu] ratios. These observations were also supported by optical measurements carried out through photoluminescence and absorption measurements. \- In order to gain a better understanding of the influence of the extrinsic doping of the CuGaSe2 films and why many attempts towards the type inversion in the p- type CuGaSe2 compounds by varying the composition or by doping with extrinsic defects have failed, ion implantation was used to introduce Ge into CuGaSe2. Photoluminescence of the Ge containing films has evidenced the presence of new defects such as donor levels in the band gap. Electron spin resonance measurements of the Ge- containing CuGaSe2 films has highlighted an additional ESR resonance observed at g = 2.003 ascribed to donors. However, Curie paramagnetism up to room temperature for all the Ge implanted films, characteristic of localized states has been observed for this resonance. This was an indication that donor electrons are electrically inactive even at room temperature because the ESR signal at g = 2.003 is observed without change of the ESR line shape in the whole temperature range investigated. An explanation was that these donor electrons either remain bound to donors or they are trapped by a deep defect. \- It can be summarized in the present thesis that high quality CuGaSe2 films with good and reproducible growth parameters - film properties can be achieved using the CCSVT process. Extrinsic doping of CCSVT- grown CuGaSe2 films with Ge via ion implantation has given rise to new defects (ESR and PL). Interestingly, we can cite the new donor levels that are not electrical active within the band gap of the implanted films. For the first time, the electrically inactivity of the donors found in CuGaSe2 films after Ge implantation were highlighted and can explain the difficulties encountered to dope CuGaSe2 compounds.||Die vorliegende Arbeit befasst sich mit der Herstellung des halbleitenden CuGaSe2 Chalkopyrit Dünnschichten mittels CCSVT (Chemical closed- space vapor transport) Verfahren bei der Vervendung von einer Ga2Se3- Quelle und einem HCl/ H2 Transport-Trägergasgemisch, mit sehr hohen Depostionsraten (d »1μm/min), und letztlich bei niedrigen Substrattemperaturen (Tsubstrate « 520°C). Danach wurde die Untersuchung der undotierte CuGaSe₂ Schichteigenschaften und die Untersuchung der Ge dotierten CuGaSe2 Schichteigenschaften durchgeführt. \- Der erste Schwerpunkt dieser Doktorarbeit ist die Abscheidung von hochwertigen CuGaSe2- Dünnschichten. Hierbei wurde untersucht die Reproduzierbarkeit der geeigneten CCSVT Prozessparameter, die hohe CuGaSe2 Kristallqualität erreichen können. Als Hauptaufgabe wurde eine Korrelation zwischen den CCSVT- Prozessparametern und den strukturellen und morphologischen Eigenschaften des CuGaSe2 erarbeitet. Es wurde gezeigt, dass ein zwei Stufenprozess erforderlich ist, um die Reproduzierbarkeit der Korrelation mit der Eigenschaften des CuGaSe2 zu erreichen. \- Der zweite Schwerpunkt dieser Arbeit ist eine umfassende Studie von der CCSVT CuGaSe₂ Schichteigenschaften über eine Kombination von optischen Eigenschaften mittels Transmission, Reflexion und Photolumineszenz Spektroskopie und strukturellen Eigenschaften mittels XRD, EDX, TEM und ERDA Messungen. Es wurde gezeigt dass, Ga sich an der Rückseite von CCSVT CuGaSe2 Dünnschichten anhäuft. \- In dem letzten Teil wurde die Ge Dotierung des CuGaSe2 Dünnschichten mittels Ion Implantation und die Untersuchung dieser dotierte CuGaSe2- Dünnschichten mittels Photolumineszenz und Elektron Spin Resonanz durchgeführt. Hierbei wurde insbesondere der Einfluss des Ge- Fremdelements auf die Eigenschaften des CuGaSe2 Dünnschichten untersucht. Mit Hilfe von Temperatur- und Anregungsleistungsabhängigen Photolumineszenz Experimenten, wurde neue Defekte in der Bandlücke der Ge dotierten Dünnschichten identifiziert. Interessantweise, ist der tiefe Donator Niveau mit Ionizierungsenergie E = 360±10 meV. In Tieftemperatur ESR Untersuchungen von Ge dotierten CuGaSe2 Dünnschichten wurde eine Resonanz (g = 2.003) beobachtet, die einen für Donator typischen g- Wert hat und die sich mit der Temperaturerhöhung nicht verändert (Curie Verhalten)","https://refubium.fu-berlin.de/handle/fub188/2348||http://dx.doi.org/10.17169/refubium-6549","urn:nbn:de:kobv:188-fudissthesis000000003161-4","eng","http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen","Ge- ion implantation||CuGaSe2||CCSVT","500 Naturwissenschaften und Mathematik::530 Physik::530 Physik","Characterization of as-grown and Ge - ion implanted CuGaSe2 thin films prepared by the CCSVT technique","Charakterisierung von undotierten und Ge- implantierten CuGaSe2 Dünnschichten hergestellt mit CCSVT- Verfahren","Dissertation","free","open access","Text","Physik","FUDISS_derivate_000000003161","FUDISS_thesis_000000003161","http://www.diss.fu-berlin.de/2007/657/"