Improvement in current density of nano- and micro-structured Si solar cells by cost-effective elastomeric stamp process

Kiseok Jeon,Sangwoo Lim,Chaehwan Jeong,Min Joon Park,Hongsub Jee

doi:10.1063/1.5013298

Abstract

Effective incident light should be controlled for improving the current density of solar cells by employing nano- and micro-structures on silicon surface. The elastomeric stamp process, which is more cost effective and simpler than conventional photolithography, was proposed for the fabrication of nano- and micro-structures. Polydimethylsiloxane (PDMS) was poured on a mother pattern with a diameter of 6 μm and a spacing of 2 μm; then, curing was performed to create a PDMS mold. The regular micropattern was stamped on a low-viscosity resin-coated silicon surface, followed by the simple reactive ion etching process. Nano-structures were formed using the Ag-based electroless etching process. As etching time was increased to 6 min, reflectance decreased to 4.53% and current density improved from 22.35 to 34.72 mA/cm2.

Highlights

In recent years, nano- and micro-structures have been investigated for cost-effective solar cell applications with better performance
The micro-structures are formed regularly, as shown in Fig. 2(a), and the nano-structures are uniformly distributed on the micro-structures; UV resin is effective as an etching mask
They react with the sidewall of the combined nano- and micro-structure (CNMS) because of increase in the aspect ratio; this results in decrease in etching rate

Summary

Introduction

Nano- and micro-structures have been investigated for cost-effective solar cell applications with better performance. There are several methods of fabricating micro-structures on silicon surface, such as deep reactive ion etching,[5] catalytic vapor–liquid–solid chemical vapor deposition,[6] micro-contact printing,[7] electron beam lithography,[8] and X-ray lithography.[9] these processes have limitations owing to expensive equipment and materials, such as photo masks, contact aligners, and tracking systems for cost-effective solar cells, and the usage of toxic chemicals as developer and photoresist. The metal-assisted chemical etching (MACE) process has been considered as a simple and cost-effective tool for fabricating nano-structures.[12,13,14] As mentioned above, a combined nano- and micro-structure (CNMS) can improve the performance of solar cells through mutual supplementation

Methods

Results

Conclusion