Formation and Luminescent Properties of Oxidized Porous Silicon Doped with Erbium by Electrochemical Procedure

Abstract

The present work is concerned with Er-doped oxidized porous silicon (PS). The characteristic feature of the work is that PS doping has been realized by an electrochemical procedure followed by a high temperature treatment. 5-μm thick PS layers were formed on p-type Si of 0.3-Ohm-cm resistivity. Er incorporation was performed by a cathodic polarization of PS in a 0.1 M Er(NO3)3 aqueous solution. A high temperature treatment in an oxidizing ambient at 500-1000°C was utilized to provide either partial or total oxidation of PS:Er layers. X-ray microanalysis was used to study chemical composition of the samples. Photoluminescence (PL) and photoluminescence excitation (PLE) spectra were investigated. After the partial oxidation (in the temperature range of 600-800°C), weak Er3+-related PL at 1.53 ptm was observed. A high temperature anneal in Ar atmosphere at the temperature of 1100°C caused a significant increase in the Er3+-related PL intensity. Resonant features were observed in PLE spectra of fully oxidized PS. Five peaks at 381, 492, 523, 654 and 980 nm were revealed. The strongest excitation occurred at 381 and 523 nm. The excitation of different Er3+ energy levels, cross-relaxation interactions and emission due to the 4I13/2→4I15/2 transitions were considered. Application of the Er-doped oxidized PS for integrated optical waveguides is presented.

Photoluminescence from erbium incorporated in oxidized porous silicon

“…This strongly suggests that Er ions are the most efficient luminescence centres. PL spectra of this type are characteristic of fully oxidized PS:Er [8]. Fig.…”

“…The PL spectra of the samples oxidized at 500-700°C reveal a weak band at 750 nm, which is attributed to a non-oxidized silicon clusters in PS, and a weak broad emission band between 1000 and 1400 nm. PL spectra of this type are characteristic of partially oxidized PS:Er containing silicon clusters [8].…”

“…The samples were oxidized at 500-1000°C in an O 2 atmosphere for 20 min followed by an anneal at 1100°C for 15 min in an Ar environment. Oxidation at 500-700°C followed by annealing at 1100°C allowed us0 to fabricate POPS containing silica and silicon clusters [8]. Oxidation at 900-1000°C followed by annealing at 1100°C allowed to fabricate FOPS containing silica.…”

“…OPS waveguides are presently passive devices and incorporating rare-earth element Er into OPS offers a way to realize optical planar waveguide amplifiers operating at the third telecommunication window (i.e. 1.5 lm) [8,9]. These amplifiers are attractive due to their small size and potential integration with other optical devices.…”

“…These amplifiers are attractive due to their small size and potential integration with other optical devices. OPS as host media for Er is of great interest because: (a) due to open porosity, Er can be incorporated deeply into PS before oxidation; (b) by combining the 0925 PS oxidation regimes at different temperature and atmospheres, PS can be controllably oxidized, obtaining Si nanoclusters and Er ions incorporated in OPS [4,5,8,9].…”