Single Crystalline Germanium-Lead Alloy on Germanium Substrate Formed by Pulsed Laser Epitaxy

Abstract

Single crystalline germanium-lead alloy (GePb) is synthesized for the first time using pulsed laser induced epitaxy. Amorphous GePb with Pb content of 3% was deposited on Ge substrate and followed by pulsed laser annealing. Two sets of laser fluence, 300 mJ/cm2 and 400 mJ/cm2, were used in this work. The as-grown GePb alloy has good crystalline quality, as confirmed by transmission electron microscopy. No dislocation or Pb precipitation is found in the GePb layer. High-resolution Rutherford Backscattering Spectrometry (HRBS) characterization indicates that substitutional Pb content in the GePb alloy is 0.2 ± 0.1%. There is a substantial loss of Pb atoms after GePb formation according to the HRBS results. More serious Pb outdiffusion is observed for the sample annealed at 400 mJ/cm2 than that annealed at 300 mJ/cm2.