【摘要】 本文研究了SiO2和Si层的厚度分别为2-8nm和1.5-3nm的Si/SiO2超晶格在交流电场下的电致发光特性。以超晶格中SiO2层内加速的过热电子碰撞激发纳米Si层中密集的硅量子点,获得了Si/SiO2超晶格蓝绿色交流电致发光。Si/SiO2超晶格的电致发光亮度随电压升高呈现指数增强,最高发光亮度可达到1.4cd/m2。随着Si层厚度的增加,Si/SiO2超晶格电致发光谱的低能侧发光峰相对增强,可以归结为纳米Si层厚度对其中硅量子点尺寸分布的限制作用。当超晶格中SiO2层厚度小于过热电子的平均自由程时,过热电子的平均能量减小导致短波侧的发光强度迅速下降,电致发光强度随之迅速降低。更多还原

【Abstract】 The alternating-current（AC） electroluminescence properties of the Si/SiO₂ superlattices were studied with the thicknesses of SiO₂ and Si layers of 2-8nm and 1.5-3nm,respectively.Under the AC field,blue-green EL of Si/SiO₂ superlattices is observed when the Si quantum dots in Si layers are impacted by the hot electrons from SiO₂ layers.With the increase of the applied voltage,the brightness of the electroluminescence increases exponentially,and the maximum brightness is 1.4cd/m².With the decrease of Si layer thickness,the high energy peaks in the spectrum are enhanced relatively,which may be attributed to the reduction of Si quantum dot size limited by the thickness of the silicon layers. When the SiO₂ layer in the superlattices is thinner than the hot electron mean free path,the average energy of the hot electrons reduced,leading to a decrease of the electroluminescence intensity as well as the EL peaks at higher photon energy.更多还原