Victor G. Karpov - Physics of Thin-Film Photovoltaics

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Scrivener Publishing100 Cummings Center, Suite 541J Beverly, MA 01915-6106

Publishers at Scrivener

Martin Scrivener ( martin@scrivenerpublishing.com) Phillip Carmical ( pcarmical@scrivenerpublishing.com)

Victor Karpov

and

Diana Shvydka

This edition first published 2022 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA

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Library of Congress Cataloging-in-Publication Data

ISBN 9781119651000

Cover image: Pixabay.comCover design by Russell Richardson

Set in size of 11pt and Minion Pro by Manila Typesetting Company, Makati, Philippines

Printed in the USA

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To our parents

There is no longer a need to argue about the importance of solar energy and the necessity of furthering the photovoltaic (PV) industry. These issues have been addressed by many sources in the media and publications. Excellent books have been published covering the basics of photovoltaics including both the underlying classical physics and material implementations.

Taking advantage of the above issues sufficiently presented, this book will concentrate on several subjects left beyond the scope of the exiting photovoltaic texts. These subjects are all related to thin film photovoltaics (such as CdTe, CIGS, or a-Si:H based) whose properties and operations turn out to be quite different from that of the classical PV presented mostly by the crystalline Si structures. The obvious differences lie in the device thinness (microns instead of millimeters) and its morphology (polycrystalline or amorphous instead of crystalline).

The thinness effect may be so significant that the photogenerated charge carriers reach the electrodes without much recombination even in the imperfect non-crystalline material, which deemphasizes the classical concept of recombination limited PV performance. On the other hand, the transversal resistance not self-averaging across thin disordered structures leaves a possibility of significant lateral nonuniformities, some of which can be quite detrimental. In addition, the non-crystalline morphology leads to continuous energy spectra of localized states instead of discrete levels in crystals, which results in new transport mechanisms (hopping) and recombination features. Finally, an important part of thin film PV possess piezo-electric properties, which leads to the concept of piezo-PV unknown in the classical PV science.