SiOx luminescence from light-emitting porous silicon: Support for the quantum confinement/luminescence center model

Abstract

Measurements of hydrogen loss and luminescence as a function of annealing temperature in porous silicon suggest that luminescence is attributable to electron-hole recombination in SiOx surface layers with an intensity that is dependent upon the surface hydrogen content. The luminescence is composed of three Gaussian bands similar to those found in amorphous SiO2. X-ray photoelectron spectroscopy and scanning electron microscopy show porous silicon has SiOx on the surface, which is comprised of many particles of about 10 nm size. Collectively, the data strongly support the previously proposed quantum confinement/luminescence center model.

The origin of blue and ultraviolet emission from porous GaP

“…For example, there is experimental evidence for luminescence mechanisms based on excitation in nanosized Si and deexcitation via luminescent centers in amorphous Si or SiO x surface layers. [8][9][10] In a recent publication Anedda et al reported blue and UV emission from porous GaP ͑a III-V semiconductor͒ which they explained by quantum size effects. 11 From the blueshift of the emission the size of the GaP structures was estimated to be 25 Å.…”

Nondegrading Photoluminescence in Porous Silicon

“…In recent years, most of the research has been directed at understanding the origin of the luminescence [1][2][3][4][5][6][7][8] and fabricating PS-based light emitters [9][10][11][12]; but the problems of the degradation [2,13,14] and the relatively low efficiency [15] of the photoluminescence (PL) remain unsolved. The PL degradation subsequent to normal PS preparation, accompanied with a blueshift of the peak position, is generally believed to originate from the chemical instability of the PS surface [2,13,14]. Under the attack of oxygen, the Si-H bonds on the surfaces of the Si nanocrystallites will be broken and the quantity of the Si dangling bonds will increase.…”

Nanoporous silicon tubes: the role of geometry in nanostructure formation and application to light emitting diodes

“…The F band luminescence, usually centered between 420 and 500 nm, decays on the nanosecond time scale. This can be observed on porous silicon samples aged in air or intentionally oxidized, and is thought to originate from structural defects in the silicon nanocrystal oxide shell, or from the luminescence of very small silicon nanocrystals [19,39,[69][70][71][72]. Other PL bands have been previously reported for porous silicon: the so-called UV band (centered around 350 nm), and the R band (ranging from 1100-1500 nm) [59].…”

“…The spectrum obtained at the necklace has a higher S/F intensity ratio compared to the spectrum obtained at the tube tip/walls. The F band is related to the defects at the silicon/silicon oxide interface [69,70,73]. The necklace region corresponds to the area where the tube is actively forming.…”