Tampere University of Technology

TUTCRIS Research Portal

Thermally evaporated single-crystal Germanium on Silicon

Research output: Contribution to journalArticleScientificpeer-review

Details

Original languageEnglish
Pages (from-to)8037-8040
Number of pages4
JournalThin Solid Films
Volume519
Issue number22
DOIs
Publication statusPublished - 1 Sep 2011
Publication typeA1 Journal article-refereed

Abstract

Using conventional and polarization-dependent Raman spectroscopy we investigate the structural properties of Germanium films thermally evaporated on Silicon under various conditions. The analysis suggests that the Ge films can be crystalline, amorphous and poly-oriented, depending on the substrate temperature. We use both comparison with Raman spectra of Ge films grown on amorphous substrates and polarization-dependent Raman measurements to demonstrate that in the 250-450 °C interval, crystalline Ge films are epitaxial. This result is validated by means of large angle X-ray diffraction measurements. We employ these films to fabricate and characterize near infrared heterojunction photodiodes that exhibit high responsivities and low dark current densities.

Keywords

  • Germanium, Near infrared, Photodetectors, Raman characterization, Thermal evaporation