Laser-induced Greenish-Blue Photoluminescence of Mesoporous Silicon Nanowires

Abstract

Solid silicon nanowires and their luminescent properties have been widely studied, but lesser is known about the optical properties of mesoporous silicon nanowires (mp-SiNWs). In this work, we present a facile method to generate greenish-blue photoluminescence (GB-PL) by fast scanning a focused green laser beam (wavelength of 532 nm) on a close-packed array of mp-SiNWs to carry out photo-induced chemical modification. The threshold of laser power is 5 mW to excite the GB-PL, whose intensity increases with laser power in the range of 5–105 mW. The quenching of GB-PL comes to occur beyond 105 mW. The in-vacuum annealing effectively excites the GB-PL in the pristine mp-SiNWs and enhances the GB-PL of the laser-modified mp-SiNWs. A complex model of the laser-induced surface modification is proposed to account for the laser-power and post-annealing effect. Moreover, the fast scanning of focused laser beam enables us to locally tailor mp-SiNWs en route to a wide variety of micropatterns with different optical functionality, and we demonstrate the feasibility in the application of creating hidden images.

A Focused Laser Beam: A Useful and Versatile Tool for 1D Nanomaterials Research: A Review

“…Evidently, with increasing laser power, darker red colors were seen from the pruned regions and the corresponding PL peaks gradually right-shift. The optical property modification of mesoporous Si nanowires was also facilitated by the laser pruning method and demonstrated by Choi et al [17] . To account for the optical shifts, the authors proposed a complex model of laserinduced surface modification to account for the laser-power and post-annealing effect.…”

“…Besides directed patterning of 1D CNT arrays, the focused laser beam technique can also be employed to other 1D semiconductors including Si nanowires [17] , CuO nanowires [18] , GeSe 2 nanoribbons [19] and even ternary CdS x Se 1ex nanobelts [20] . By changing [11].…”

“…5(cee)). Besides enhancement to the hydrophobicity of the pristine CNTs array, the hydrophobic and hydrophilic property of CNTs could be flexibly interconverted by combined applications of the oxygen reactive ion etching (RIE) and focused laser beam technique [17] . It is found that oxygen RIE treatment can change the CNTs surface from hydrophobic to hydrophilic.…”

Applications of Raman spectroscopy in archaeometry: An investigation of pre-Columbian Peruvian textiles

“…Confocal microspectrofluorimetry is an alternative which is being successfully applied in pigments and dyes identification (Claro et al, 2008(Claro et al, , 2010. Raman microscopes can also be used as microspectrofluorimeters (Oakley et al, 2011, Dyer andSmith, 1995;Choi et al, 2014), benefiting from a much better spatial resolution and confocality than dedicated equipment (Turrell and Corset, 1996), however, to our knowledge it was never used with this purpose in archaeometry. Thus, even when fluorescence or other type of luminescence cannot be avoided and precludes the detection of Raman bands, a Raman microscope can still be used to obtain the emission spectrum from specific spots.…”

White light from annealed porous silicon: Broadband emission from violet to the near infrared

“…However, a full understanding on the processes and the mechanisms involved in the light emission from these materials have not been achieved and are still under debate [1]. Several models have been proposed to explain the visible photoluminescence (PL) from PS, the quantum confinement (QC) and the quantum confinement/ luminescent centers (QCLC) models being the most widely invoked [2].…”