Introduction

Abstract

Ellipsometry is an optical technique from which the optical constants (refractive indexn and extinction coefficient k), dielectric function and absorption coefficient (α) of materials are characterized. The performance of solar cells is essentially governed by the light absorption characteristics of semiconducting light absorbers incorporated into solar cells and the understanding of the absorber optical properties is crucial for the interpretation and improvement of the device performance. In particular, the optical processes in solar cells, including unfavorable light absorption and back-side reflection by a metal layer, are determined primarily by the optical constants of solar-cell component layers. Accordingly, accurate knowledge of the layer optical properties is essential to maximize solar-cell conversion efficiencies. From ellipsometry measurements, layer structures of solar cells can also be characterized non-destructively. In this chapter I review the fundamental principles and basic idea of the ellipsometry technique. This chapter will also provide an overview for the contents of subsequent chapters in this book.