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Identifier

uch.physics.phd//1993DIS0162

Title

Absorption and localization of light in amorphous semiconductor thin films and multilayers

Alternative Title

Απορρόφηση και εντοπισμός του φωτός σε άμορφα ημιαγωγικά λεπτά υμένια και υπερπλέγματα

Author

Κονδύλης, Αντώνιος Ι.

Thesis advisor

Τζανετάκης, Παναγιώτης

Abstract

My work focusses on two subjects. The first deals with the thermal variation of the absorption edge of hydrogenated amorphous silicon (a-Si:h), in the temperature range between 100k and 500k. The experimental technique used is the measurement of transmittance and reflectance spectra. We measure a-Si:H samples prepared by different deposition methods. The gap's thermal variation that we find is in agreement with literature. The variation of the Urbach parameter from 100k to 500k is found to be less than 5meV. This result agrees with that derived from recent measurements of an other group, which used a new experimental technique, namely, total yield electron spectroscopy. On the contrary it is in opposition to the widely accepted correlation between the gap and the disorder parameter suggested by Cody. As to the second subject, it deals, theoretically, with the effect of disorder on the propagation of electromagnetic waves through binary multilayer structures. The disorder is introduced in the form of variable layer thickness. The results show that the volume density of the electromagnetic power decays, on the average, exponentially with depth. The localization length, the characteristic length associated with this exponential decay is calculated numerically as well as analytically. The approximate analytical formula derived is in excellent agreement with the exact numerical results within a broad wavelength range.

Language

Greek

Issue date

1993-11-01

Date available

1997-06-6

Collection

School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses

Type of Work--Doctoral theses

Permanent Link

https://elocus.lib.uoc.gr//dlib/0/5/b/metadata-dlib-1993DIS0162.tkl