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用 Si H4 气体的减压 CVD法 ,在氧化硅以及石英基板上自然形成了高密度的 (～ 10 11cm-2 )纳米尺寸的半球状硅晶粒 (硅量子点 ) ,并且对其光学吸收和发光 (Photo- luminescence,PL)特性进行了评价。用表面热氧化了的硅量子点样品 ,在室温条件且在高于 1.2 e V以上的能量范围内观察到了 PL谱。随着量子点尺寸的减少 ,PL谱的光学吸收限移向高能方向。 PL谱的峰值能呈现大幅度的 (约 0 .9e V)斯塔克移动 ,并且 PL谱的强度几乎与温度无关 ,说明发光来自与局域能级相关联的发光和复合过程。
High-density (~10 11 cm -2) nano-sized hemispherical silicon grains (silicon quantum dots) are naturally formed on silicon oxide and quartz substrates by the reduced-pressure CVD method of Si H 4 gas, and their optical absorption and Photo-luminescence (PL) characteristics were evaluated. With surface thermally oxidized silicon quantum dot samples, PL spectra were observed at room temperature and over energies above 1.2 eV. As the size of the quantum dots decreases, the optical absorption of the PL spectrum shifts to the higher energy direction. The peak of the PL spectrum can exhibit a large (about 0.9 eV) Stark shift, and the intensity of the PL spectrum is almost independent of temperature, indicating that luminescence comes from the luminescence and recombination processes associated with local energy levels.