RECENT PROGRESS OF THE AMORPHOUS SILICON SOLAR CELLS AND THEIR TECHNOLOGY

Abstract
A review is given on the current state of the art in the field of amorphous silicon solar cells and key technology to improve cell performance. Remarkable advantages of this new material for low cost photovoltaic devices are pointed out, and discussed in view of both device physics and manufacturability. A new concept of the drift type photovoltaic effect in terms of the field dependent photocarrier generation process and carrier collection efficiency is introduced. Optimization of photovoltaic performance in p-i-n junction and inverted p-i-n junction devices is examined with some experimentally determined physical constants, and realistic limit of the conversion efficiencies in the p-i-n homojunction and heterojunction solar cells are also clarified. Some new approaches with heterojunction, solar cells utilizing wide band gap amorphous silicon carbide and micro-crystalline silicon are also demonstrated. Progress in the conversion efficiencies and cell performances in various types of amorphous silicon solar cells are surveyed.