Acknowledgment

FIRST AND FOREMOST I want to thank my adviser Prof. Tibor Grasser for opening the floodgates to the world of microelectronics and giving me the opportunity to join his research group. He did not get tired of motivating me to work at the Institute for Microelectronics for several projects over the years, whereby he only failed once temporarily when I left for the Himalayas. He impressed me not only with his persistent way of solving scientific problems but also with his widely diversified talents from social capabilities to playing the piano in an amazing manner. Sometimes, I envy him for the length of his days, which must be 48 hours at least...

I thank Prof. Emmerich Bertagnolli for serving on my examination committee. Furthermore, I am indebted to Prof. Siegfried Selberherr for the excellent working conditions, the opportunity to attend several scientific conferences, and not at last the calm working climate at the Institute, which serves as a basis for world-class scientific work. I also thank Prof. Erasmus Langer, the head of the Institute for Microelectronics, who delighted long working days with his sarcastic comments regularly. Prof. Hans Kosina impressed me with his deep theoretical knowledge as well as his ability to pass it on. He always found the time to answer my questions, even during the most hectic days.

Gerhard Span provided me with the industrial background of my work as well as the confidence to represent him at two conferences on short notice. It was always a pleasure to collaborate in an uncomplicated and productive way.

The history of my roommates at the Institute is not too short. Johannes Mesa introduced me to the Institute and was always open for discussions. His regular phone calls to the western parts of Austria considerably extended my vocabulary. At the same time, we shared our room with Mahdi Pourfath, whom I thank for occasional cultural discussions. He impressed me with a phenomenal diligence and endless working hours. Later, Martin Vasicek joined our room, who accompanied me on an essential part of my theoretical derivations and soon became a good friend. Special thank goes to him for uncountable discussions on semiconductor physics, computer problems, our fatherhood, or just the source of our daily lunch. The last year, Wolfgang Gös shared our room, whom I have never seen in a bad temper.

I want to thank the proofreaders of this thesis, who greatly improved this work by their numerous suggestions. Enzo Ungersböck supported me on several issues on Monte Carlo simulations. His deep physical background and programming skills combined with his calm nature and modesty made him a good colleague and friend. The man behind his tie, Stefan Holzer proved to solve even the trickiest optimization tasks with just the adaption of one or two short scripts. I remember Vassil Palankovski for his elaborate knowledge on hetero-structure devices as well as his ingenious tactics on research and publication, who was one of the Institute's biggest coffee sinks. I do not remember even one weekend at the office, when he was not also there.

I had the pleasure to attend numerous conferences on three continents with a couple of colleagues. Siddhartha Dhar accompanied me to India and the USA, whereby interestingly his navigational skills where developed far better in New York than in his hometown, Delhi. My fascination for his homeland and his openness served as a basis for a good friendship. The outcome of a trip to Mexico together with Gerhard (Monte-)Karlowatz was an impressive number of high-quality photographs. The attendance of a summer school in Grenoble together with Philipp Schwaha and Oliver Triebl as well as a conference in Nice together with Alexandre Nentchev opened essential insights to the French cuisine.

Probably the Institute's most successful "hacker" was Johann Cervenka. His disrespect for complicated code constructs within MINIMOS-NT has turned out to be very useful on several occasions. Besides his support in many cases, I want to thank him and all other colleagues who spent plenty of their leisure time on the professional administration of the computer network. Special acknowledgment goes to Robert Entner for infecting me with a deep devotion for Linux.

Markus Karner proved to host brilliant ideas below his amazing tailwind haircut. His immortal optimism was one of the cornerstones for the software projects we collaborated on, whose quality has been ensured by one of the most destructive software testers I know, Oskar Baumgartner.

My namesake Paul-Jürgen Wagner not only amused me with his humorous comments, but also had an open ear for countless questions regarding the typesetting system L^ATEX. Whenever I got stuck in some theoretical questions, Viktor Sverdlov had the right Russian book and some helpful translations for me. Andreas Gehring and Wilfried Wessner were always good conversation partners whenever my inner motor requested some motivation refill.

If I had the right to, I would award Gregor Meller as the Institute's universal genius. There was not a single topic he could not handle in a well-founding presentation of at least 15 minutes immediately.

Manfred Katterbauer, Ewald and Christoph Haslinger, and Renate Winkler took care of the administrative work at the Institute, which is much too often totally undervalued. Thank goes to all former members of the Institute for Microelectronics for leaving a precious heritage for all coming generations and to all other colleagues for their assistance and the stimulating working atmosphere they created.

Above all, I want to thank my family. My parents made possible all of my studies by their continuous support, which they gave as a matter of course. Obviously, my father's recommendation not to come after his profession was not fruitful... While my mother-in-law Elfi assisted me with countless little things she handled, Peter detached me from my laptop from time to time in order to remind me of the beauty of our neighborhood. More than any other support, my better half Lena provided me with love and understanding for endless working days. She encouraged and assisted me whenever possible. Only she knows how much I am indebted to her. And of course there is Jakob, most probably the best achievement of my life!

M. Wagner: Simulation of Thermoelectric Devices