Modelling picosecond and nanosecond laser ablation for prediction of induced damage on textured SiN_x/Si surfaces of Si solar cells

Abstract

This study investigated the laser‐induced damage arising from 266 and 532 nm laser ablation of SiNx films on alkaline textured Si surfaces with nanosecond and picosecond pulse durations using a combination of optical‐thermal simulations and measurements of carrier recombination current density. Simulations predict that the melting depth is limited to within 150 nm of the SiNx/Si surface after 266 nm ps laser irradiation due to the greater absorption in both the SiNx and Si resulting in more direct ablation, while temperatures exceeding the melting temperature of Si are predicted to extend up to 1000 nm into the Si substrate with 532 nm ps pulses leading primarily to spallation. Ablation of the SiNx by 266 nm ps irradiation is predicted to be more homogeneous on smaller sized pyramids due to the increased absorption of double‐bounce reflected light on the pyramid faces. This finding has implications for applications requiring uniform ablation of dielectrics on textured Si surfaces. Ablation of SiNx by the longer wavelength 532 nm ps pulses also increases carrier recombination compared to that incurred with 266 nm ps pulses due to the increased melting depth. Longer ns pulses result in less steep temperature gradients and, for 266 nm pulses, an increased melting depth compared to ps pulses. Consequently, shorter ps UV pulses are preferred for SiNx ablation on Si surfaces due to their reduced laser damage penetration, whereas the less steep temperature gradients resulting from ns 532 nm pulses are beneficial for laser doping to form selective emitters.

Single-Step Fabrication of Resonant Silicon–Gold Hybrid Nanoparticles for Efficient Optical Heating and Nanothermometry in Cells

“…Resonant dielectric Si NPs were fabricated using the laser ablation in liquid (LAL) method. ,, This approach is environmentally friendly due to the absence of toxic chemical reagents; it is also straightforward and can be scaled for mass production . Moreover, this method allows control over the shape, size, and morphology of the fabricated NPs by varying the irradiation laser parameters.…”

“…10,11,22 This approach is environmentally friendly due to the absence of toxic chemical reagents; it is also straightforward and can be scaled for mass production. 23 Moreover, this method allows control over the shape, size, and morphology of the fabricated NPs by varying the irradiation laser parameters. For instance, to obtain Si NPs, we used a femtosecond laser with a wavelength of 1030 nm, frequency of 1 MHz, and pulse energy of 10 μJ, which was focused on a silicon substrate immersed in water.…”

Eco-friendly Approach for Creation of Resonant Silicon Nanoparticle Colloids

“…Producing resonant NP colloids using a fs laser has been studied and discussed in detail. − Although a fs laser provides a more efficient ablation, it is the ns pulse duration that is superior in terms of fabrication productivity. Indeed, during ns laser ablation, the material output is much higher …”

“…Indeed, during ns laser ablation, the material output is much higher. 25 The inherent nature of the ns laser interaction with the solid-state volume involves the subsequent heating and melting processes during the pulse, as opposed to the interaction with the electron system in the case of the fs pulse. 26 Moreover, during ns laser fabrication of colloids, the additional fragmentation process within pulse duration can take place.…”

Improvement of Laser-Induced Damage on High-Efficiency Solar Cells via Top-Hat Beam Ablation

“…The Gaussian beam is composed of inhomogeneous irradiation, so a homogeneous removal was not possible by using a Gaussian beam. The absorption of light is predicted to be dependent not only on the laser parameters but also on the geometry [19], and a homogeneous removal is also not possible since the pyramids can lead to laser intensity amplifications [20]. Compared with a textured surface, a polished surface was used to reduce the dislocations mostly formed at the pyramid tips, which absorb more energy from the laser source [11].…”