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Identifier

000411493

Title

Epitaxial growth and characterization of III-Nitride thin films and heterostructures for photovoltaic applications

Alternative Title

Επιταξιακή ανάπτυξη και χαρακτηρισμός λεπτών υμενίων και ετεροδομών ΙΙΙ-Νιτριδίων για φωτοβολταϊκές εφαρμογές

Author

Παπαδομανωλάκη, Έλενα

Thesis advisor

Ηλιόπουλος, Ελευθέριος

Abstract

In the present work, the MBE growth of InGaN is thoroughly studied, with the goal to shed light to the kinetic processes that govern it, to eliminate inhomogeneities and phase separation, to achieve better control over the alloy composition, and to optimize the conditions for films of desirable structural and optoelectronic properties. The role of substrate temperature on InGaN growth is investigated as well as its effect on the kinetic mechanisms of InGaN decomposition and In desorption. The temperature’s influence on structural and optoelectronic properties of InGaN alloys is also examined. Low temperatures seem to favor the growth of uniform, homogenous films with no phase separation. A correlation is found between alloy inhomogeneities and different structural defects with the films’ optoelectronic properties. Next, the process of InGaN thermal decomposition is examined. A quantitative model for the decomposition rate is extracted. A window for the optimum growth conditions for InGaN alloys of different composition is determined. Indium adsorption and desorption processes are also studied in this work. Desorption rates were measured, and the dependence of the desorption rate on the indium coverage of the surface is investigated. A quantitative was to correlate the coverage with kinetic processes is suggested. Finally, some initial work on InGaN heterostructures and photovoltaic devices is presented. The structures discussed include InGaN/GaN multiple quantum well (MQW) structures, InGaN/p-Si(111) heterostructures, as well as two preliminary photovoltaic devices.

Language

English

Subject

IN desorption

InGaN decomposition

Indium Gallium Nitride

Molecular beam epitaxy

Phase separation

Photovoltaics

Διαχωρισμός φάσης

Εκρόφηση IN

Επιταξιακή ανάπτυξη με μοριακές δέσμες