Effect of Rapid Thermal Annealing on the Photoluminescence from Si Nanocrystal Decorated Si Nanowires Array Grown by a Metal Assisted Chemical Etching Method

Abstract

In this report, the micron-long Si nanowires (NWs) array is grown by a metal assisted chemical etching (MACE) process using Ag as the noble metal catalyst in HF/H 2 O 2 solution.These Si NWs are decorated with arbitrary shaped ultrasmall Si nanocrystals (NCs) due to the side wall etching of the Si NWs. The MACE grown samples exhibit strong PL emission in the visible region and quantum confinement (QC) effect of photon in the Si NCs is believed to be the dominant mechanism behind PL. We have investigated the influence of rapid thermal annealing with different annealing environments on the optical properties (such as PL, Raman and reflectivity) of the Si NCs decorated Si NWs samples to gain better insight into the QC effect. The effect of laser excitation power on the PL properties of the as-grown Si NCs/NWs sample are also inspected in this report for further confirmation of QC effect behind the PL emission profile.

Silicon nanowire heterostructures for advanced energy and environmental applications: a review

“…ZnO has been deposited on Si NWs by different techniques, e.g., atomic layer deposition (ALD), CVD, solution synthesis, and RF magnetron sputtering, to fabricate Si NW/ZnO device prototypes [73][74][75][76][77][78]. Ghosh et al reported Si NW/ZnO film core-shell HSs formed by sputtering of ZnO film on MACE-grown Si NWs and studied their photoluminescence spectral evolution [74,108]. Figures 3(a) and (b) show the FESEM top-view and cross-sectional-view images of the Si NW/ZnO core-shell HS, respectively [74].…”

“…The Si NW/hematite (α-Fe 2 O 3 ) core-shell HS system was studied by Mayer et al for photoelectrochemical (PEC) water splitting at low applied potentials [82]. Note that the Si NWs are very reactive in air ambient and this results in a native SiO x (0x2) layer on the surface of the Si NWs [20,22,74,99,[107][108][109]. The SiO x layer on the Si NWs often plays a crucial role to modify the optoelectronic and mechanical properties of the Si NWs due to the presence of different kinds of defect in the Si-SiO x interface.…”

“…The SiO x layer on the Si NWs often plays a crucial role to modify the optoelectronic and mechanical properties of the Si NWs due to the presence of different kinds of defect in the Si-SiO x interface. In some cases, the SiO x layer was intentionally grown on Si NWs to form Si NW/SiO x HSs [20,22,74,99,[107][108][109]. Figure 3(c) shows a typical diffraction contrast TEM image of a Si/SiO x NW HS grown by PLD [20].…”

“…Traditionally, compound semiconductors with direct bandgap have been mostly exploited for the fabrication of LEDs. Despite Si having an indirect bandgap, Si NWs can emit light at room temperature with tunable wavelengths depending on their size, doping and surface conditions [22,103,[107][108][109][145][146][147][148]. Various mechanisms, including the quantum confinement (QC) effect and surface state or defects, have been proposed for the origin of light emission, though this is an ongoing debate [22,103,[107][108][109][145][146][147][148].…”

Efficient visible light photocatalysis and tunable photoluminescence from orientation controlled mesoporous Si nanowires

“…Over the past few decades, Si nanowires (NWs) have been attracting a great deal of attention in both basic scientic research and technological applications due to their unique physical and chemical characteristics. [1][2][3][4][5][6][7] Si NWs grown by metal assisted chemical etching (MACE) have been employed as an active component in various electronic and optoelectronic devices, e.g., eld effect transistors, 6 light emitting diodes, 2 solar cells, 1 sensors, 4 energy storage 3 and photochemical reactors 5 etc. The elucidation of the morphology controlled growth of single crystalline Si NWs is critical to understanding the fundamental physics of NWs to design and fabricate Si NWs based innovative nano-devices with tunable characteristics.…”