1 research outputs found
Toward Truly Single Crystalline GeTe Films: The Relevance of the Substrate Surface
The growth of GeTe thin films on
a Si(111)-(√3 × √3)ÂR30°-Sb
surface is reported. At growth onset, the rapid formation of fully
relaxed crystalline GeTe(0001)-(1 × 1) is observed. During growth,
a GeTe(0001)-(√3 × √3)ÂR30° surface reconstruction
is also detected. Indeed, density functional theory (DFT) simulations
indicate that the reconstructed GeTe(0001)-(√3 × √3)ÂR30°
structure is energetically competing with the GeTe(0001)-(1 ×
1) reconstruction. The out-of-plane α-GeTe<0001>||Si<111>
and in-plane α-GeTe<−1010>||Si<−211>
epitaxial
relationships are confirmed by X-ray diffraction (XRD). Suppression
of rotational twist and reduction of twinned domains are achieved.
The formation of rotational domains in GeTe grown on Si(111)-(7 ×
7) is explained by domain matched coincidence lattice formation with
the Si(111)-(1 × 1) surface. Atomic force microscopy (AFM) images
show the coalescence of well-oriented islands with subnanometer roughness
on their top part. van der Pauw measurements are performed to verify
the electric properties of the films. The quality of epitaxial GeTe
thin film is discussed and related to the crystalline structure of
GeTe and its rhombohedrally distorted resonant bonds