Freestanding Thin‐Films: Water‐Assisted Liftoff of Polycrystalline CdS/CdTe Thin Films Using Heterogeneous Interfacial Engineering (Adv. Mater. Interfaces 14/2019)
- Award ID(s):
- 1711885
- PAR ID:
- 10169719
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 6
- Issue:
- 14
- ISSN:
- 2196-7350
- Page Range / eLocation ID:
- 1970095
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Vanadium oxide V3O5 exhibits an insulator-to-metal transition (IMT) near 430 K, which is the highest value for all vanadium oxides exhibiting IMTs. This makes it interesting for advanced electronic applications. However, the properties of V3O5 have been little studied, and, in particular, there are no reports of experimentally determined mechanical properties. In this work, Young’s modulus of sputter-deposited V3O5 thin films has been determined by measuring the fundamental resonant frequency of V3O5-coated silicon microcantilevers using a laser beam deflection technique. After deposition, the films were characterized by x-ray diffraction, resistivity measurements, and atomic force microscopy. The value of Young’s modulus experimentally determined for V3O5 was 198 ± 14 GPa, which is slightly lower than the computationally derived values for bulk crystal V3O5.more » « less
-
Sb thin films have attracted wide interest due to their tunable band structure, topological phases, high electron mobility, and thermoelectric properties. We successfully grow epitaxial Sb thin films on a closely lattice-matched GaSb(001) surface by molecular beam epitaxy. We find a novel anisotropic directional dependence on their structural, morphological, and electronic properties. The origin of the anisotropic features is elucidated using first-principles density functional theory (DFT) calculations. The growth regime of crystalline and amorphous Sb thin films was determined by mapping the surface reconstruction phase diagram of the GaSb(001) surface under Sb2 flux, with confirmation of structural characterizations. Crystalline Sb thin films show a rhombohedral crystal structure along the rhombohedral (211) surface orientation parallel to the cubic (001) surface orientation of the GaSb substrate. At this coherent interface, Sb atoms are aligned with the GaSb lattice along the [1̄10] crystallographic direction but are not aligned well along the [110] crystallographic direction, which results in anisotropic features in reflection of high-energy electron diffraction patterns, misfit dislocation formation, surface morphology, and transport properties. Our DFT calculations show that the preferential orientation of the rhombohedral Sb (211) plane may originate from the GaSb surface, where Sb atoms align with the Ga and Sb atoms on the reconstructed surface. The formation energy calculations confirm the stability of the experimentally observed structures. Our results provide optimal film growth conditions for further studies of novel properties of Bi1−xSbx thin films with similar lattice parameters and an identical crystal structure, as well as functional heterostructures of them with III–V semiconductor layers along the (001) surface orientation, supported by a theoretical understanding of the anisotropic film orientation.more » « less
An official website of the United States government

