Effect of Metallic Ions on Photoluminescence of Porous Silicon

2010 ◽  
Vol 663-665 ◽  
pp. 641-644 ◽  
Author(s):  
Bao Gai Zhai ◽  
Ming Meng ◽  
Qing Lan Ma ◽  
Yuan Ming Huang

In the present paper, we have not only investigated the top surface and cross-section morphology, but also measured photoluminescence spectra characteristic of porous silicon after deposition of metallic ions by electrochemical deposition employing scanning electron microscopy (SEM) and spectrometer, respectively. It is apparent from the SEM images that the microstructure of porous silicon is seriously ruined by the metallic ions deposited by electrochemical deposition. Most interesting is the finding that in the photoluminescence spectrum of porous silicon after the deposition of metallic ions such as AL3+ and Cu2+, the luminescence band gradually is quenched as the electrochemical deposition progressed. A careful consideration of the results obtained show that according to the basic theory of well-established quantum confinement model, the quenching of photoluminescence spectra of porous silicon may well be attributed to the microstructure fell into ruin. On the other side of the fence, we can interpret the physical origin of the phenomenon in view of the presence of metallic ions which give rise a series of energy level deep in the band gap of porous silicon.

1991 ◽  
Vol 256 ◽  
Author(s):  
David L. Naylor ◽  
Sung B. Lee ◽  
John C. Pincenti ◽  
Brett E. Bouma

ABSTRACTPhotoluminescence spectra have been measured in porous silicon following electrochemical etching in dilute hydrofluoric acid (HF). The effects of HF concentration during etching on the efficiency and peak wavelength of photoluminescence have been investigated. The effects of temperature between 25°C and 200°C on PL spectra have been recorded. Photoluminescence lifetimes as a function of wavelength have been studied following ultrashort UV photoexcitation. A number of lifetime components in the decay are observed the longest in good agreement over the wavelength range of 500 to 600 nm with a silicon quantum wire model. At longer wavelengths a departure from lifetimes of the wire model is observed and two hypotheses for the discrepancy are presented.


1994 ◽  
Vol 332 ◽  
Author(s):  
H.Z. Song ◽  
L.Z. Zhang ◽  
B.R. Zhang ◽  
G.G. Qin

ABSTRACTIt was found that porous silicon (PS) layers formed on 0.01 Ωcm (111) and 0.02 Ωcm (100) Si substrates show high photoluminescence (PL) peak energies on both lower and higher porosity sides and a minimum of PL peak energy at the moderate porosity, while those formed on 0.8 and 10Ωcm (111) p-type Si substrates show an increase of PL peak energy with porosity on the lower side and a saturation of PL peak energy with porosity on the higher side. These experimental facts are not consistent with the quantum confinement model for light emission of PS, which predicts a monotonous increase of PL peak energy with PS porosity.


2010 ◽  
Vol 663-665 ◽  
pp. 1032-1035
Author(s):  
Bao Gai Zhai ◽  
Qing Lan Ma ◽  
Ming Meng ◽  
Yuan Ming Huang

In this article, we report on the observations that in the aqueous electrolyte of aluminum nitrate, the thin metallic conducting films on both internal and external surface of porous silicon (PS) thin films that emit visible photoluminescence at room temperature prior to electrochemical deposition have been obtained under electrochemical deposition condition. Add to this high surface-to-volume ratio and these make it a good candidate for the catalyst supporter. We have investigated the surface morphology of PS after the interval of about 30 hours of electrochemically deposited aluminum by means of scanning electron microscopy (SEM). It has been shown from SEM images that not only micrometer-sized pores are smoothed by deposition of aluminum microcrystal, but also the presences of semi-sphere aluminum microcrystal which rooted in the tip of micrometer-sized pores are observed. On the one hand, this extremely interesting phenomenon which the micrometer-sized pores are smoothed may be explained in terms of principle of electrochemical deposition; on the other hand, we have laid the formation mechanism of semi-spherical aluminum microcrystal at the door of Gibbs free energy.


1993 ◽  
Vol 298 ◽  
Author(s):  
T. Van Buuren ◽  
T. Tiedje ◽  
W. Weydanz

AbstractHigh resolution measurements of the silicon L-edge absorption in electrochemically prepared porous silicon show that the absorption threshold is shifted to higher energy relative to bulk silicon, and that the shift is dependent on how the porous silicon is prepared. When the porous silicon is made from n-type material with light exposure, the blue shift increases logarithmically with the anodizing current. Porous silicon prepared by anodizing p-type silicon exhibits a blue shift in the L-edge which increases with the time spent in the HF solution after the anodizing potential is turned off. The data are consistent with the quantum confinement model for the electronic structure of porous silicon.


1993 ◽  
Vol 298 ◽  
Author(s):  
P.M. Fauchet ◽  
E. Ettedgui ◽  
A. Raisanen ◽  
L.J. Brillson ◽  
F. Seiferth ◽  
...  

AbstractUsing 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.


2004 ◽  
Vol 96 (1) ◽  
pp. 197-203 ◽  
Author(s):  
D. W. Cooke ◽  
R. E. Muenchausen ◽  
B. L. Bennett ◽  
L. G. Jacobsohn ◽  
M. Nastasi

1994 ◽  
Vol 358 ◽  
Author(s):  
P. D. J. Calcott ◽  
K. J. Nash ◽  
L. T. Canham ◽  
M. J. Kane

ABSTRACTThe spectroscopic evidence that the main visible photoluminescence (PL) band of porous silicon (the 'S' band) originates from quantum confined crystalline silicon is presented, and arguments that claim to invalidate this evidence are analysed in detail. We find that a careful study of all the spectroscopic data provides strong support for the quantum confinement model. Additionally we consider the interesting issue of the luminescence spectrum of a single silicon quantum dot.


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