Temperature-Dependent Photoluminescence of Silicon Nanoporous Pillar Array

Abstract

Silicon nanoporous pillar array (Si-NPA) is a micron-nanometer hierarchical structure which might be used as functional substrates for constructing optoelectronic nanodevices. This makes understanding the photoluminescence (PL) from Si-NPA important. We measure the PL of Si-NPA in the range of 11-300 K. By analyzing the evolution of the peak energy and intensity with temperature, the ultraviolet, blue, orange and red PL bands from Si-NPA are attributed to the radiative recombination through the deep-levels in silicon oxide, oxygen-related defect states in silicon nanocrystallites (nc-Si), band-to-band transition within nc-Si, and surface/interface states of nc-Si or between nc-Si and SiO𝑥, respectively. At least two non-radiative recombination processes, which are activated at different temperature ranges, are proposed for the PL intensity variation with temperature. These results might provide strong foundations for designing and constructing optoelectronic devices based on silicon nanostructures.

Influence of Buffer Agent Concentration on the Optical Properties from CdS Nanocrystals on Silicon Nanoporous Pillar Array

“…Through analyzing the data, a linear fit can be obtained with the tiny slop of ∼−0.01 meV per mol L −1 , which indicates that the peak energy of blue emissions is hardly dependent on the buffer agent concentration. The average peak energy is ∼2.82 eV (∼440 nm) which is consistent with the previous results [15]. The green emissions originate from the near band gap of CdS nanocrystals [9,14,23].…”

“…The morphologies of prepared CdS/Si-NPA with the different concentration of buffer agent are displayed in Figure 2. Obviously, the characteristic of the regular array of Si-NPA is maintained in CdS/Si-NPA [15], and both the pillars and the valleys are covered by the CdS films. From Figure 2(a), some flocculation and big size particles can be observed and pell-mell pilled on the pillars and between the pillars and valleys.…”

“…Si-NPA was prepared by hydrothermally etching (111) oriented, p-type single crystal silicon (sc-Si) wafers in the aqueous solution of hydrofluoric acid containing ferric nitrate, the procedure and conditions of which have been described in detail elsewhere [15]. The CdS thin film was deposited on Si-NPA by a CBD method and the preparing procedures were described as follows.…”

Time-Resolved Photoluminescence Study of Silicon Nanoporous Pillar Array

“…On the other hand, the experimental results obtained by temperature-dependent PL measurements gave almost the completely contrary conclusion. [16] Such a physical ambiguity has now become an obstacle for designing and constructing Si-NPA-based optoelectronic devices.…”

Room-temperature excitonic emission with a phonon replica from graphene nanosheets deposited on Ni-nanocrystallites/Si-nanoporous pillar array

“…The emission peak showed a regular dependence with temperature, in which the peak located at 525 nm exhibited intensity attenuation and the peak intensity of emission peak at 425 nm inversely became strong. This effect can be primarily attributed to the change in the thermal occupation of bound and free excitons [ 29 , 32 , 33 ]. Thus, given the temperature evolution of the PL spectrum, the peaks at approximately 525 and 425 nm should be attributed to bound and free excitonic emission, respectively.…”