Enhancement of Thermal Stability in Photoluminescence by Carbonization of Porous silicon

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J. Korean Ceram. Soc. > Volume 34(5); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(5): 467.

다공성실리콘의 탄화를 이용한 PL의 열적안정성 증진

최두진, 서영제, 전희준, 박홍이¹, 이덕희¹

연세대학교 세라믹공학과
¹연세대학교 물리학과

Enhancement of Thermal Stability in Photoluminescence by Carbonization of Porous silicon

ABSTRACT

Porous silicon was prepared by an anodic etching. The pore size was about 10 nm at an etching time of 20 sec and a current density of 20 mA/$textrm{cm}^2$. The porous layer was composed of an micro-porous layer (0.6 ${mu}{textrm}{m}$) and a macro-porous layer (10 ${mu}{textrm}{m}$). Room temperature PL with maximum peak 6700$AA$ appeared. The peak disappeared by an oxidation reaction when the porous silicon was heated to 100~20$0^{circ}C$ in atmosphere. In order to avoid the oxidation a heat treatment was done in H2 atmosphere. The micro-pore and Si column, which formed quantum well, were collapsed by the high temperature. The PL maximum peak of heated sample was gradually red-shifted and showed about 300$AA$ red-shift at 50$0^{circ}C$. The intensity of PL was maintained to high temperatures in lower pressures. The porous Si was carbonized in C2H2+H2 gas in order to increase thermal stability. The carbonization of the porous Si prevented red-shift of the maximum PL peak caused by sintering effect at high temperatures, and the carbonized porous Si showed Pl signal at higher temperatures by above 20$0^{circ}C$ than the sample in H2 atmosphere.

Key words: Porous silicon, Photoluminescence(PL), Carbonization, Thermal stability