As seen in Fig. 2, the porous silicon surface is the most effective
medium to reduce reflection. It is also seen that the porous
silicon surface has little or no angular dependence as seen in
Fig. 2(a)–(d). However, we can clearly see aweak angular dependence
for all other textured surfaces. It is also apparent that the chemically
textured surface with ARC displays an angular dependence that is
similar to the laser textured sample. We have also carried out
Monte Carlo based ray tracing (TracePro from Lambda Research
Corp.) to simulate the optical characteristics of thermally
annealed ultrafast laser textured silicon surfaces. The simulation
results are included in Fig. 2(b). It can be seen that the simulation
results closely match the experimentally measured values. The
small deviation of the simulated results from the experimental
values can be attributed to surface roughness, feature size
variation, etc. in our samples, which have not been included in
the simulations. Thus, it is clear that light trapping in the ultrafast