Isothermal close space sublimation for II-VI semiconductor filling of porous matrices

Vicente Torres-Costa,Claudia De Melo,Fernando Argulló-Rueda,Osvaldo De Melo,Aurelio Climent-Font

doi:10.1186/1556-276x-7-409

Abstract

Isothermal close space sublimation, a simple and low-cost physical vapour transport technique, was used to infiltrate ZnTe and CdSe semiconductors in porous silicon. The structure of the embedded materials was determined by X-ray diffraction analysis while Rutherford backscattering spectra allowed determining the composition profiles of the samples. In both cases, a constant composition of the II-VI semiconductors throughout the porous layer down to the substrate was found. Resonance Raman scattering of the ZnTe samples indicates that this semiconductor grows in nanostructured form inside the pores. Results presented in this paper suggest that isothermal close space sublimation is a promising technique for the conformal growth of II-VI semiconductors in porous silicon.

Highlights

Porous silicon (PS) has received a lot of interest in recent years due to its many peculiar properties
The temperatures were selected taking into account previous growth experiments of thin films; they represent the lower limits of the temperature range in which CdSe and ZnTe can be grown by isothermal close space sublimation (ICSS)
X-ray diffraction (XRD) and Rutherford backscattering spectroscopy (RBS) measurements revealed that stoichiometric polycrystalline ZnTe and CdSe are formed

Summary

Introduction

Porous silicon (PS) has received a lot of interest in recent years due to its many peculiar properties. Its porosity may reach up to 90% under appropriate conditions [1], and its internal surface may be as high [2] as 800 m2/cm; this makes PS a promising material for catalytic applications and as a matrix material for embedding different substances such as SnO2 [3], C60 molecules [4] or even nematic liquid crystals [5]. The interest in embedding materials in PS originates from different reasons. Luminescence stability of porous silicon is related to the passivation of its internal surfaces. The small pores of silicon can be used as templates for nanocrystal formation. Potential PS-based optoelectronic devices require electrical contacts in the external surface on the PS film, and in the internal walls of the pores

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Results

Conclusion