摘 要
本實驗採取熱蒸鍍法先在不同基板上成長奈米晶矽，並利用變化退火時的氧氣壓力(4.8mTorr ~ 1atm)與溫度(300oC ~ 1200oC)而改變此奈米晶矽所形成的量子點結構。樣品則以光激發螢光(photoluminescence，PL)實驗與掃描式電子顯微鏡(scanning electron microscope)分析之。
我們發現本實驗所成長的奈米晶矽與基板種類沒有太大的關係。此外，由PL訊噪比(S/N ratio)可以得知，若固定退火時的氧氣壓力，當退火溫度為600oC時，或在固定退火溫度下，退火時氧氣壓力為100mTorr，我們可以得到較佳的樣品。
接著利用低溫光激發螢光實驗，可以推測量子點的活化能大約為161meV。最後，我們提出奈米晶矽的氧化模型，解釋當量子點尺寸變化時PL譜線卻不改變之原因。

Abstract
The experiment takes thermal evaporation method to synthesis nc-Si. First, we deposit nc-Si on different substrates. Second, we adjust the O2 pressure (4.8mTorr ~ 1atm) and the temperature (300oC ~ 1200oC) in annealing to affect the structure of QDs which is formed by the nc-Si. Then we use photoluminescence, PL, experiment and scanning electron microscope, SEM, to analyze samples。
We find that nc-Si which grown in this experiment doesn’t have much relatedness with the differences between substrates. Besides, we can tell from PL single to noise ratio that we can get the better sample no matter we fix O2 pressure when the annealing temperature is 600oC or control the O2 pressure at 100mTorr under the fixed annealing temperature.
After this, we can use low temperature PL technology to get that activation energy, Ea, of QDs is about 161meV. Finally, we propose the model of nc-Si on oxidation to explain the reason that why the PL lineshape doesn’t change when size of QDs has changed.

[1]Leigh Canham, Gaining light from silicon, Nature, 408,411(2000)
[2]L. Pavesi, L. Dal Negro, C. Mazzoleni, G. Franzò and F. Priolo, Optical gain in silicon nanocrystals, Nature, 408,440(2000)
[3]J. Ruan, P. M. Fauchet, L. Dal Negro, M. Cazzanelli, and L. Pavesi, Stimulated emission in nanocrystalline silicon superlattices, Applied Physics Letters,83,5479(2003)
[4]Bernard Gelloz and Nobuyoshi Koshida, Electroluminescence with high and stable quantum efficiency and low threshold voltage from anodically oxidized thin porous silicon diode, Journal of Applied Physics,88,4319(2000)
[5]Gong-Ru Lin, Chun-Jung Lin, Chi-Kuan Lin, Li-Jen Chou and Yu-Lun Chueh, Oxygen defect and Si nanocrystal dependent white-light and near-infrared electroluminescence of Si-implanted and plasma-enhanced chemical-vapor deposition-grown Si-rich SiO2,Jounal of Applied Physics,97,094306(2005)
[6]A. R. Wilkinson and R. G. Elliman, The effect of annealing environment on the luminescence of silicon nanocrystals in silica, Journal of Applied Physics,96,4018(2004)
[7]Jan Valenta, Robert Juhasz, and Jan Linnros, Photoluminescence spectroscopy of single silicon quantum dots, Applied Physics Letters,80,1070(2002)
[8]Yoshihiko Kanemitsu, Tetsuo Ogawa, Kenji Shiraishi, and Kyozaburo Takeda, Visible photoluminescence from oxidized Si nanometer-sized spheres: Exciton confinement on a spherical shell , Physical Review B ,48, 4883 (1993)
[9]L. Dal Negro, M. Cazzanellia, N. Daldossoa, Z. Gaburroa, L. Pavesia, F. Priolob, D. Pacificib, G. Franzòb and F. Iaconac, Stimulated emission in plasma-enhanced chemical vapour deposited silicon nanocrystals, Physica E: Low-dimensional Systems and Nanostructures,16,297(2003)
[10]L. Dal Negro, M. Cazzanelli, L. Pavesi, S. Ossicini, D. Pacifici, G. Franzò, F. Priolo and F. Iacona, Dynamics of stimulated emission in silicon nanocrystals, Applied Physics Letters, 82,4636(2003)
[11]H. Morisaki, F. W. Ping, H. Ono, and K. Yazawa , Above-band-gap photoluminescence from Si fine particles with oxide shell, Journal of Applied Physics ,70,1869(1991)
[12]H. Morisaki, H. Hashimoto, F. W. Ping, H. Nozawa, and H. Ono, Strong blue light emission from an oxygen-containing Si fine structure, Journal of Applied Physics, 74,2977(1993)
[13]H. S. Chen, J. J. Chiu and T. P. Perng, On the photoluminescence of Si nanoparticles, Materials physics and mechanics,4,62(2001)
[14]C. G. Granqvist and R. A. Buhrman, Ultrafine metal particles, Journal of Applied Physics ,47, 2200(1976)
[15]Shigeki Yatsuya, Susumu Kasukabe and Ryozi Uyeda, Formation of Ultrafine Metal Particles by Gas Evaporation Technique. I. Aluminium in Helium , Japanese Journal of Applied Physics,12,1675(1973)
[16]施敏 原著,黃調元 譯,半導體元件物理與製作技術 第二版,國立交通大學出版社,台灣,556(2002)
[17]D. R. Vij, Luminescence of Solids, Plenum Press, New York ,Ch3,95(1998)
[18]A. D. Yoffe, Low-dimensional systems: quantum size effects and electronic properties of semiconductor microcrystallites (zero-dimensional systems) and some quasi-two-dimensional systems., Advances in Physics, 42 ,173(1993)
[19]G. Ledoux, O. Guillois, D. Porterat, and C. Reynaud, Photoluminescence properties of silicon nanocrystals as a function of their size, Physical Review B ,62,15942(2000)
[20]Ho-Sang Kwack, Yuanping Sun, Yong-Hoon Cho, Nae-Man Park and Seong-Ju Park, Anomalous temperature dependence of optical emission in visible-light-emitting amorphous silicon quantum dots, Applied Physics Letters,83,2091(2003)
[21]S. Gardelis, J. S. Rimmer, P. Dawson, B. Hamilton, R. A. Kubiak, T. E. Whall, and E. H. C. Parker, Evidence for quantum confinement in the photoluminescence of porous Si and SiGe, Applied Physics Letters, 59,2118(1991)
[22]L. W. Yu, K. J. Chen, L. C. Wu, M. Dai W. Li, and X. F. Huang ,Collective behavior of single electron effects in a single layer Si quantum dot array at room temperature , Physical Review B,71,245305(2005)
[23]Shaoyun Huang, Souri Banerjee, Raymond T. Tung, and Shunri Oda, Quantum confinement energy in nanocrystalline silicon dots from high-frequency conductance measurement, Journal of Applied Physics ,94,7261(2003)
[24]Toshihide Takagahara and Kyozaburo Takeda, Theory of the quantum confinement effect on excitons in quantum dots of indirect-gap materials, Physical Review B, 46, 15578(1992)
[25]B. E. Deal and A. S. Grove, General Relationship for the Thermal Oxidation of Silicon, Journal of Applied Physics,36,3770(1965)
[26]W. Z. Shen and S. C. Shen, Photoluminescence studies of strained CdTe/Cd0.633Mn0.367Te single quantum wells, Journal of Applied Physics,80,5941(1996)