**Meet the editor**

Dr. Leonid A. Kosyachenko is professor of National University of Chernivtsi, Ukraine. After receiving his Doctor of Sciences Degree in Physics and Mathematics in 1983, he founded and became a head of Optoelectronics Department – the first department of this kind at Ukrainian universities. About twenty of his pupils have performed work to obtain the degrees of Candidate

(Ph.D.) and Doctor of Sciences. His research interests have been in physics and technology of solar cells, semiconductor X-ray and γ-ray detectors, light-emitting and photosensitive devices. He is author (co-author) of several books and numerous scientific articles; presented reports at international scientific conferences and meetings in Germany, Italy, England, Japan, China, Greece, Spain, Belgium, Russia. He was the leader of several collaborative projects with the institutions of Russia, Belorussia and is one of the leaders of the long-term projects of the European Commission. Prof. L.A. Kosyachenko is a member of the Ukrainian Physical Society and the guest editor of journal "Solar Energy Materials and Solar Cells".

Contents

**Preface IX** 

and Djoko Hartanto

Chapter 2 **Epitaxial Silicon Solar Cells 29**  Vasiliki Perraki

Purnomo Sidi Priambodo, Nji Raden Poespawati

Chapter 3 **A New Model for Extracting the Physical Parameters** 

N. Nehaoua, Y. Chergui and D. E. Mekki

Chapter 4 **Trichromatic High Resolution-LBIC: A System for** 

and Joaquín Martín-Calleja

Chapter 6 **Possibilities of Usage LBIC Method** 

Chapter 7 **Producing Poly-Silicon from Silane** 

B. Erik Ydstie and Juan Du

Jiri Vanek and Kristyna Jandova

**in a Fluidized Bed Reactor 125** 

Chapter 9 **Optical Insights into Enhancement of Solar** 

Chapter 5 **Silicon Solar Cells:** 

**from I-V Curves of Organic and Inorganic Solar Cells 53** 

**the Micrometric Characterization of Solar Cells 67**  Javier Navas, Rodrigo Alcántara, Concha Fernández-Lorenzo

**Structural Properties of Ag-Contacts/Si-Substrate 93** 

**Cell Performance Based on Porous Silicon Surfaces 179**  Asmiet Ramizy, Y. Al-Douri, Khalid Omar and Z. Hassan

Ching-Hsi Lin, Shih-Peng Hsu and Wei-Chih Hsu

**for Characterisation of Solar Cells 111** 

Chapter 8 **Silicon-Based Third Generation Photovoltaics 139**  Tetyana Nychyporuk and Mustapha Lemiti

Chapter 1 **Solar Cell 1** 

### Contents

#### **Preface** XI


X Contents



### Preface

The third book of four-volume edition of "Solar Cells" is devoted to solar cells based on silicon wafers, i.e., the main material used in today's photovoltaics. Single-crystalline Si (c-Si) modules are among the most efficient but at the same time the most expensive since they require the highest purity silicon and involve a lot of stages of complicated processes in their manufacture. Polycrystalline silicon (mc-Si) cells are less expensive to produce solar cells but are less efficient. As a result, cost per unit of generated electric power for c-Si and mc-Si modules is practically equal. Nevertheless, wafer silicon technology provides a fairly high rate of development of solar energy. Photovoltaics of all types on silicon wafers (ribbons), representatives of the so-called first generation photovoltaics, will retain their market position in the future. In hundreds of companies around the world, one can always invest with minimal risk and implement the silicon technology developed for microelectronics with some minor modifications.

For decades, an intensive search for cheaper production technology of silicon waferbased solar cells is underway. The results of research and development, carried out for this purpose, lead to positive results although too slowly. This book includes the chapters that present new results of research aimed to improve efficiency, to reduce consumption of materials and to lower the cost of wafer-based silicon solar cells as well as new methods of research and testing of the devices contributing to the achievement of this goal. Light trapping design in c-Si and mc-Si solar cells, solarenergy conversion as a function of the geometric-concentration factor, design criteria for spacecraft solar arrays are considered in several chapters. A system for extracting the physical parameters from I-V curves of solar cells and PV solar generators, the micrometric characterization of solar cells, LBIC method for characterization of solar cells, and a new model for non-idealities in the I-V characteristic of the PV generators are discussed in other chapters of the volume.

It is hoped that this volume of "Solar Cells" will be of interest for many readers.

The editor addresses special thanks to the contributors for their initiative and high quality work, and to the technical editors that conveyed the text into a qualitative and pleasant presentation.

> **Professor, Doctor of Sciences, Leonid A. Kosyachenko** National University of Chernivtsi Ukraine

**1** 

**Solar Cell** 

*Indonesia*

*Universitas Indonesia*

Purnomo Sidi Priambodo, Nji Raden Poespawati and Djoko Hartanto

Solar cell is the most potential energy source for the future, due to its characteristics of renewable and pollution free. However, the recent technology still does not achieve high Watt/m2 and cost efficiency. Solar cell technology still needs to be developed and improved further to obtain optimal efficiency and cost. Moreover, in order to analyze and develop the solar cell technologies, it is required the understanding of solar cell fundamental concepts. The fundamentals how the solar works include 2 phenomena, i.e.: (1) Photonics electron

The phenomenon of photonics electron excitation is general nature evidence in any materials which absorbs photonic energy, where the photonic wavelength corresponds to energy that sufficient to excite the external orbit electrons in the bulk material. The excitation process generates electron-hole pairs which each own quantum momentum corresponds to the absorbed energy. Naturally, the separated electron and hole will be recombined with other electron-holes in the bulk material. When the recombination is occurred, it means there is no conversion energy from photonics energy to electrical energy, because there is no external electrical load can utilize this natural recombination energy. To utilize the energy conversion from photonic to electric, the energy conversion process should not be conducted in a bulk material, however, it must be conducted in a device which has rectifying function. The device with rectifying function in electronics is called diode. Inside diode device, which is illuminated and excited by incoming light, the electronhole pairs are generated in *p* and *n*-parts of the *p-n* diode. The generated pairs are not instantly recombined in the surrounding exciting local area. However, due to rectifying function, holes will flow through *p*-part to the external electrical load, while the excited electron will flow through *n*-part to the external electrical load. Recombination process of generated electron-hole pairs ideally occurs after the generated electrons-holes experience energy degradation after passing through the external load outside of the diode device, such

The conventional structure of p-n diode is made by crystalline semiconductor materials of Group IV consists of silicon (Si) and germanium (Ge). As an illustration in this discussion, Si diode is used, as shown in Figure-1 above, the sun light impinges on the Si p-n diode, wavelengths shorter than the wavelength of Si bandgap energy, will be absorbed by the Si material of the diode, and exciting the external orbit electrons of the Si atoms. The electron excitation process causes the generation of electron-hole pair. The wavelengths longer than the wavelength of Si bandgap energy, will not be absorbed and not cause excitation process

excitation effect to generate electron-hole pairs in materials and (2) diode rectifying.

**1. Introduction** 

as shown in illustration on Figure-1.
