TITLE:
Nanocoatings on 2D Macroporous Silicon Structures
AUTHORS:
Liudmyla Karachevtseva, Mykola Kartel, Bo Wang, Oleg Lytvynenko, Yurii Sementsov
KEYWORDS:
Macroporous Silicon, Surface Nanocrystals, SiO2 Layers, Photoluminescence, High-Pressure Oxidation
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.7 No.7,
July
10,
2019
ABSTRACT:
Macroporous silicon formed by photoanodic etching with high aspect ratio and large effective surface is one of the promising materials for the development of 2D photonic structures. We fabricated nanocoatings of CdTe, ZnO, CdS surface nanocrystals and SiO2 layers on macroporous silicon surface. The near-IR optical absorption was investigated and well-separated oscillations with giant amplitude were observed in the spectral ranges of surface level absorption. This process is because of resonance electron scattering on the surface impurity states with the difference between two resonance energies equal to the Wannier-Stark ladder. Macroporous silicon structures with SiO2 nanolayers and CdS nanocrystals are proposed to enhance the photoluminescence of CdS nanoparticles with quantum yield 28%. Addition functionalization of 2D macroporous silicon is a result of the high-pressure oxidation. The structural SiO2 reorganization to orthorhombic phase increases the concentration of paramagnetic Pb centers, EPR signal amplitude and GHz radiation absorption.