Silicon nanoporous pillar array: a silicon hierarchical structure with high light absorption and triple-band photoluminescence

Abstract

A silicon hierarchical structure, silicon nanoporous pillar array (Si-NPA), was prepared by a hydrothermal etching method. The architecture of Si-NPA was characterized to be a regular array of micron-sized, quasi-identical and nanoporous silicon pillars with an additional porous layer beneath the array. The pore walls were proved to be consisted of a SiO(x) matrix and dispersive silicon nanocrystallites. An integral reflectivity below 4% was achieved in the wavelength range of 240-2400 nm. Three photoluminescence bands, one blue and two red, were observed at room temperature and attributed to the recombination processes through band-to-band transition and luminescent centers, respectively. The structural and physical properties indicate that Si-NPA might be as both a functional silicon nanostructure and a template for assembling silicon-based nanocomposites in fabricating optoelectronic nanodevices.

Correlation between reflectivity and photoluminescent properties of porous silicon films

“…However, when the etching duration is increased from 8 to 30 min the PL peak shows a red shift. The explanation of such type of peak shifts of PL emission of PS samples is given by two types of models, one the most common model is quantum confinement model and second one is quantum confinement luminescent center (QCLC) model [8). According to the quantum confinement model, PL emission is due to band to band transition and is dependent on the size of Si crystallites; smaller crystallites size shifts the emission peak to shorter wavelengths.…”

“…numerous interesting silicon nanostructures such as PS. the arrays of nanocone, nanopillars, nanorods and nanowires have been developed by traditional or newly invented methods, and many interesting optical or electrical properties were obtained, but the space remained for constructing and developing novel silicon nanostructures is still tremendous [8], The first application of photoelectrochemically formed PS layers grown on Si wafers as an ARC was reported by Prasad et al [9].…”

Near‐Infrared Light Emission from a GaN/Si Nanoheterostructure Array

“…[ 19 ] And the Si-NPA has proven to be a versatile functional substrate for constructing Si-based nanoheterostructures, such as CdS/Si-NPA with three-primary-color photoluminescence (PL) and an excellent electrical rectifi cation effect. [ 20 , 21 ] In this work, we will show a promising NIR LED prepared by growing GaN nanograins onto Si-NPA, from which a strong NIR EL peaked at ∼ 826 nm was obtained.…”

“…Si-NPA was prepared by a hydrothermal etching method [ 19 ] and its structural features were characterized by a regular array consisted of micron-sized, quasi-identical and nanoporous silicon pillars ( Figure 1 a). The GaN/Si-NPA nanoheterostructure was obtained by growing GaN on Si-NPA through a chemical vapor deposition (CVD) method.…”

“…These results might provide a brand-new approach to design ∼ 3.4 eV, respectively. If we consider that Si-NPA possesses a similar nanoporous structure than that of porous silicon (PS), [ 19 ] the electron affi nity of Si-NPA can be regarded as the same as that of PS. [ 28 ] When the heterojunction between GaN and Si-NPA was formed, a band discontinuity would occur at the interface.…”