高性能SOI基GePIN波导光电探测器的制备及特性研究

本文报道了在SOI衬底上外延高质量单晶Ge薄膜并制备高性能不同尺寸Ge PIN波导光电探测器.通过采用原子力显微镜、X射线衍射、拉曼散射光谱表征外延Ge薄膜的表面形貌、晶体质量以及应变参数,结果显示外延Ge薄膜中存在约0.2%左右的张应变,且表面平整,粗糙度为1.12 nm.此外,通过暗电流、光响应度以及3 dB带宽的测试来研究波导探测器的性能,结果表明尺寸为4μm×20μm波导探测器在-1 V的反向偏压下暗电流密度低至75 mA/cm~2,在1.55μm波长处的响应度为0.58 A/W,在-2 V的反向偏压下的3 dB带宽为5.5 GHz.     

超薄氢化非晶锗膜的结构与光电性质

通过PECVD制备出了不同厚度的a-Ge∶H膜,采用Raman光谱对样品进行了结构表征,由椭圆偏振光谱仪得到样品的厚度和光学常数,并计算了样品的光学带隙。由变温电导率分析了薄膜的电学输运性质,结果表明,载流子的传输机制为扩展态电导。进而利用变温PL谱研究了薄膜的发光性能,发现其发光峰在1.63 μm处;随着膜厚的减小,峰位和峰形都有改变,且强度明显提高。进一步分析发现,随着膜厚的减小非辐射复合跃迁的激活能增大,从而导致辐射复合过程增强。     

Further developments in quantitative X‐ray photoelectron spectromicroscopy: preliminary results from the study of germanium corrosion

The moisture‐induced corrosion of an evaporated germanium film has been observed and studied using quantitative X‐ray photoelectron spectromicroscopy. The application of recently reported software for the processing of multi‐spectral image datasets (particularly noise reduction) to this real‐world problem revealed the formation of oxide islands above the continuous passive oxide layer. The software has been developed to map the thickness of these structures within the XPS sampling depth, with a spatial resolution of a few microns. This exemplifies a characterisation methodology of use in any situation where (non‐uniform) surface modification results in chemically shifted components of the same core level (or Auger peak) between the original substrate and new overlayer. Copyright © 2005 John Wiley & Sons, Ltd.