2015 CAP Congress / Congrès de l'ACP 2015

Ge:Mn Dilute Magnetic Semiconductor

15 Jun 2015, 16:15

15m

CCIS L2-190 (University of Alberta)

Oral (Student, In Competition) / Orale (Étudiant(e), inscrit à la compétition) Condensed Matter and Materials Physics / Physique de la matière condensée et matériaux (DCMMP-DPMCM) M2-2 Material growth and processing (DCMMP) / Croissance et traitement des matériaux (DPMCM)

Speaker

Laila Obied (Brock University)

Description

This work aims to develop Ge:Mn dilute magnetic semiconductor and study the fundamental origin of ferromagnetism in this system. Using ion implantation at $77$ K, a single crystal Ge wafer was doped with magnetic Mn ions. The implantation was done at ion energy of $4.76$ MeV with a fluence of 2 x 10${}^{16}$ ion/cm${}^2$. X-ray diffraction (XRD) of the as-implanted sample showed that the implanted layer was amorphous. Therefore, different samples were annealed at $200$⁰C, $330$⁰C and $600$⁰C in a tube furnace to achieve a solid phase epitaxial regrowth of the implanted layer. XRD of the sample annealed at $330$⁰C for $33$ hours showed a polycrystalline layer. The depth profile of Mn in the as-implanted sample and the post-annealed sample at $330$⁰C was determined using secondary ion mass spectroscopy (SIMS) and it was found that some Mn diffused to the surface during the annealing. XRD of the sample annealed at $600$⁰C for $35$ minute showed peaks corresponding to an unknown phase in addition to peaks from amorphous and polycrystalline Ge. The sample annealed at $200$⁰C for $168$ hour showed no evidence of solid phase epitaxy. A SQUID was used to measure the magnetic properties of all samples. At low temperature, the as-implanted sample showed a paramagnetic behaviour. A magnetic hysteresis at $5$K and up to $200$K was observed for the samples annealed at $330$⁰C and $200$⁰C. The $600$⁰C annealed sample showed no ferromagnetic response and a significant reduction in the paramagnetic response at low temperature compared to the as-implanted sample.