Can Oxidation and Other Treatments Help Us Understand the Nature of Light-Emitting Porous Silicon?

Abstract

Using a careful analysis of the properties of light-emitting porous silicon (LEpSi), we conclude that a version of the “smart” quantum confinement model which was first proposed by F. Koch et al [Mat. Res. Soc. Symp. Proc. 283, 197 (1993)] and allows for the existence of surface states and dangling bonds, is compatible with experimental results. Among the new results we present in support of this model, the most striking ones concern the strong infrared photoluminescence that dominates the room temperature cw spectrum after vacuum annealing above 600 K.

Luminescence Bands and their Proposed Origins In Highly Porous Silicon

“…are temperature dependent, and generally nonexponential but do not vary appreciably across the 150 to 250 meV wide band. The first report of significant room temperature output from this band was that of Fauchet et al [37] with material UHV annealed at 350 "C. Many workers have attributed this band to dangling bond states on the nanocrystalline Si skeleton as first proposed by Koch in 1993 [38]. There is also an early isolated report by Perry et al [39] of efficient bulk Si-like luminescence at 1.09 eV.…”

Silicon Porosification: State of the Art

“…121 The IR band presents itself very weak at room temperature and becomes much more stronger at low temperatures. 123 The origin of the IR band seems to be related to dangling bonds.…”

Laser-induced Greenish-Blue Photoluminescence of Mesoporous Silicon Nanowires

“…PL denotes light emission under photon excitation, playing a significant role in optoelectronics. Since 1990's the PL of porous silicon has been widely studied 22 , reporting that porous silicon can emit blue (wavelength λ of 400–500 nm) 23 24 25 , blue-green ( λ centered at 490 nm) 26 , red (560–860 nm) 27 28 29 and infrared (900–2000 nm) light 30 31 32 . However, the mechanism is under debate mainly among four models, including QC, surface states, defects in oxides and specific chemical species 33 .…”