Influence of Surface Nanostructure on Silicon Light Emission
Date Issued
2005
Date
2005
Author(s)
Shiu, Chu-Chia
DOI
zh-TW
Abstract
The thesis is about influence of surface nanostructure on silicon light emission. Using silicon dioxide nanoparticles as oxide layer in metal-oxide-silicon light emission diode would enhance silicon light emission efficiency. In low temperature photoluminescence spectral measurement, SiO2 nanoparticles reduced thermal quenching effect of light emission and the efficiency was higher than pure silicon about one order of magnitude. The effect was more obvious as the decrease of the size of SiO2 nanoparticles. Through minority carrier lifetime, we found SiO2 nanoparticles did not destroy silicon quality and it still had long minority carrier lifetime. It means silicon had lower nonradiative recombination. Moreover, the surface of silicon substrate would become rough due to SiO2 nanoparticles and oxidation effect. The surface roughness would cause carrier confinement and reduce nonradiative recombination due to defect in silicon crystal. Therefore, we thought SiO2 nanoparticles help reduce surface nonradiative recombination and result in light emission efficiency enhancement.
To study about the effect of silicon nanostructure, we used laser-assisted direct imprint(LADI) to fabricate silicon surface nanostructure. We could fabricate 30nm nanorods and 30nm holes on silicon surface. In fabrication of imprint quartz mold, we fabricated 30nm gold nanoparticles on quartz as etching mask and use dry etching to form quartz mold. Then we could fabricate the same structure by LADI. We also used SiO2 nanoparticles as imprint mold to fabricate 30nm holes on silicon surface. The process is simpler than using quartz mold. In minority carrier lifetime measurement, the lifetime was decreased to 200us. It is higher than the structure fabricated by dry etching. We expected silicon nanostructure fabricated by LADI will help silicon light emission.
Subjects
矽
矽發光
奈米結構
雷射壓印
silicon
Si LED
nanostructure
LADI
Type
thesis
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