Ultrafast laser direct hard-mask writing for high efficiency c-Si texture designs

Abstract

This study reports a high-resolution hard-mask laser writing technique to facilitate the selective etching of crystalline silicon (c-Si) into an inverted-pyramidal texture with feature size and periodicity on the order of the wavelength which, thus, provides for both anti-reflection and effective light-trapping of infrared and visible light. The process also enables engineered positional placement of the invertedpyramid thereby providing another parameter for optimal design of an optically efficient pattern. The proposed technique, a non-cleanroom process, is scalable for large area micro-fabrication of high-efficiency thin c-Si photovoltaics. Optical wave simulations suggest the fabricated textured surface with 1.3 μm inverted-pyramids and a single anti-reflective coating increases the relative energy conversion efficiency by 11% compared to the PERL-cell texture with 9 μm inverted pyramids on a 400 μm thick wafer. This efficiency gain is anticipated to improve further for thinner wafers due to enhanced diffractive light trapping effects.

Micro gratings written in ZnO:Al thin films using picosecond UV‐laser interference patterning

“…For texturing ZnO:Al, a method that is simple and independent of deposition conditions is therefore of general interest in Si thin‐film photovoltaics. In recent years there have been an increasing number of publications on direct laser texturing methods to enhance light scattering or to reduce surface reflection of silicon wafers 1–5. While most of the work has been developed for texturing Si surfaces or writing of hard masks, laser‐induced periodic surface structuring (LIPSS) has also been applied to texturing of ZnO layers 6.…”

Simple fabrication of closed-packed IR microlens arrays on silicon by femtosecond laser wet etching

“…However, it is difficult to fabricate the high fill factor MLAs, and these methods require expensive equipments and complicated procedures to create the resist coating film or hardmask on the substrates. These photomasks should be pre-designed, and the shapes of the concave microstructures are not flexibly controlled [15,16].…”

Inverted Pyramidal Texturing of Silicon Through Blisters in Silicon Nitride

“…Various patterning schemes like nanoimprint lithography [4], interference lithography [5], laser texturing [6], [7] and colloidal lithography [8] have been reported for the fabrication of inverted pyramidal structures in silicon. However, the throughput for these processes may need further improvement before it is put into commercial production [4], [7]. There is a recent report of a process based on inkjet printing for the fabrication of inverted pyramids on silicon [9].…”