【摘要】 利用射频磁控溅射方法 ,在n+ Si衬底上淀积SiO2 /Si/SiO2 纳米双势垒单势阱结构 ,其中Si层厚度为 2至 4nm ,间隔为 0 .2nm ,邻近n+ Si衬底的SiO2 层厚度固定为 1.5nm ,另一SiO2 层厚度固定为 3nm .为了对比研究 ,还制备了Si层厚度为零的结构 ,即SiO2 (4.5nm) /n+ Si结构 .在经过 6 0 0℃氮气下退火 30min ,正面蒸上半透明Au膜 ,背面也蒸Au作欧姆接触后 ,所有样品都在反向偏置 (n+ Si的电压高于Au电极的电压 )下发光 ,而在正向偏压下不发光 .在一定的反向偏置下 ,电流和电致发光强度都随Si层厚度的增加而同步振荡 ,位相相同 .所有样品的电致发光谱都可分解为相对高度不等的中心位于 2 .2 6eV(5 5 0nm)和 1.85eV(6 70nm)两个高斯型发光峰 .分析指出该结构电致发光的机制是 :反向偏压下的强电场使Au/ (SiO2 /Si/SiO2 )纳米双势垒 /n+ Si结构发生了雪崩击穿 ,产生大量的电子 空穴对 ,它们在纳米SiO2 层中的发光中心 (缺陷或杂质 )上复合而发光 .更多还原

【Abstract】 The (SiO\-2/Si/SiO\-2) nanoscale double\|barrier/n\++\|Si structures with Si layers of various thicknesses were fabricated by the two\|target alternative magnetron sputtering technique. The thicknesses of the Si layers in the structures are from 2?nm to 4?nm with an interval of 0.2?nm. The control samples with Si layers of 0?nm were also made. After these structures were annealed at 600?℃ in a N\-2 ambient for 30?min, electroluminescence (EL) from the Au/SiO\-2/Si/SiO\-2/n\++\|Si structures were observed under reverse biases (n\++\|Si is biased to positive). It was found that the current and EL intensity synchronously swing with increasing Si layer thickness. All EL spectra of the samples can be decompounded into two Gaussian luminescent spectra with peaks at 1.85?eV (670?nm) and 2.26?eV (550?nm). Analysis of experimental results indicates that the EL orginates from the recombination of electrons and holes, which are produced in an avalanche process in the Au/(SiO\-2/Si/SiO\-2) nanoscale double\|barrier/n\++\|Si structure, via luminescence centers in the SiO\-2 layers.更多还原