Air-bridge-type electrodes for high-efficiency photovoltaic cell

Recently, the important issues relating to the photovoltaic cell have featured low cost and high efficiency. To make a low-cost and high-efficiency photovoltaic cell, there are many aspects such as the development of inexpensive wafers, process simplification and improvement of optical and electrical properties. In this study, the two-step texturing method using a microblaster was developed to decrease the reflection of incident lights. Bridge-type electrode structures are suggested to expand the effective surface area and decrease the series resistance of finger electrodes. The authors decided to use 10 m size powders since the efficiency of the solar cell could rather be reduced by using 50 m size powders because of their extremely rough surface. And the surface of the wafer after microblaster etching was treated with a chemical etching method using HNA (HF:HNO₃:CH₃COOH=4:9:7) solution, a dry etching method using reactive ion etching and a oxide etching method.