Peculiarities in thermal transport of nanostructured silicon arrays with different morphology

Abstract

This study explores the thermal conductivity of nanostructured porous silicon with different morphology produced by metal-assisted chemical etching of silicon wafers with different dopants, doping levels and crystallographic orientation. The wide range of morphological structures observed in the samples strongly depends on the initial wafer characteristics, a factor that cannot be neglected. While previous studies have demonstrated the qualitative capabilities of photoacoustic and Raman spectroscopy in characterizing nanostructured silicon, our work highlights the quantitative discrepancies that can arise when combining these techniques to investigate thermal properties. The differences in the results obtained using these methods can be attributed to the distinct nature of the information they provide: photoacoustic spectroscopy probes the effective thermal conductivity over larger areas, whereas Raman spectroscopy offers localized measurements. Furthermore, our Monte Carlo simulations provide insights into the morphological features of porous silicon that influence the interpretation of experimental data. This study underscores the importance of a comprehensive approach, combining both experimental and theoretical methods, to accurately assess the thermal transport properties of nanostructured materials.