多层Ge纳米晶镶嵌Si基薄膜制备与光学特性-陕西师范大学学报期刊社网站

陕西师范大学学报（自然科学版）

物理学

多层Ge纳米晶镶嵌Si基薄膜制备与光学特性

刘晓静1，高斐1*，赵卓斋2，孙文超3，张君善1，宋美周1，李宁1

(1 陕西师范大学物理学与信息技术学院，陕西西安 710062；2 陕西光伏产业有限公司，陕西西安 710051；3 西北工业大学软件与微电子学院，陕西西安 710069）

刘晓静，女，硕士研究生，主要研究方向为光电功能材料.E-mail：liuxiaojing@stu.snnu.edu.cn.*通信作者：高斐，男，教授.E-mail：feigao@snnu.edu.cn.

摘要:

采用超晶格方法，利用射频磁控共溅射及在N2气氛中退火技术，制备了多层Ge纳米晶(Ge-ncs)镶嵌Si基复合薄膜(Ge-ncs+SiO2/GeO2).同时采用椭圆偏振光谱法，研究了Ge-ncs的光学性质，并用sp3紧束缚理论模式,解释了Ge-ncs带隙宽化现象.结果表明：用超晶格方法制备的多层Ge-ncs具有密度高、尺寸和位置分布均匀的优点，纳米晶平均尺寸为9.8 nm.复合薄膜(Ge-ncs+SiO2/GeO2)具有正常色散的特性，且在1 340 nm处具有较强烈的吸收特性；Ge-ncs的光学带隙为0.82 eV，与块体Ge材料相比，Ge-ncs吸收谱显示出0.16 eV的带隙宽化.这种现象主要是由Ge-ncs中的量子限制效应导致的，采用sp3紧束缚理论模式可得到很好解释.

关键词：

多层Ge纳米晶；磁控溅射；椭圆偏振光谱法；光学特性；量子限域效应

收稿日期：

2012-03-26

中图分类号：

G633.7

文献标识码：

文章编号：

1672-4291(2012)05-0023-04

基金项目：

国家自然科学基金资助项目(61040057)；中央高校基本科研业务费专项资金项目(GK000902052).

Doi:

Fabrication and optical properties of multilayered Ge nanocrystals embedded in Si substrate

LIU Xiao-jing1, GAO Fei1*, ZHAO Zhuo-zhai2, SUN Wen-chao3,ZHANG Jun-shan1, SONG Mei-zhou1, LI Ning1

(1 College of Physics and Information Technology,Shaanxi Normal University, Xi′an 710062, Shaanxi, China；2 Shaanxi Photovoltaic Industry Limited Corporation, Xi′an 710051, Shaanxi, China；3 College of Software and Microelectronics, Northwestern Polytechnical University,Xi′an 710069, Shaanxi, China)

Abstract:

Multilayered Ge nanocrystals (Ge-ncs) with high density and better uniformity embedded in composite film (Ge-ncs+SiO2/GeO2) have been prepared by a (SiO2+Ge)/(SiO2+GeO2) superlattice method magnetron co-sputtering technique and subsequent annealing in N2 ambient. The optical properties of the prepared composite film was investigated by spectroscopic ellipsometry and the band expansion of the prepared Ge-ncs was discussed in terms of the sp3 tight binding model theory. The size of the prepared Ge-ncs is 9.8 nm. The refractive index n(λ) shows a normal dispersion and the extinction coefficient k(λ) indicates a bigger absorption characteristic around 1 340 nm. The optical band gap of the prepared Ge-ncs was determined to be 0.82 eV. As compared with bulk Ge, the multilayered Ge-ncs exhibits a certain blue shift in the absorption spectrum and a band gap expansion of 0.16 eV. The band gap expansion can be well explained by quantum confinement effect as well as the sp3 tight binding model.

KeyWords:

multilayered Ge nanocrystals; magnetron sputtering; ellipsometry; optical properties; quantum confinement effect