RESUMO
The III-V compound semiconductors exhibit superb electronic and optoelectronic properties. Traditionally, closely lattice-matched epitaxial substrates have been required for the growth of high-quality single-crystal III-V thin films and patterned microstructures. To remove this materials constraint, here we introduce a growth mode that enables direct writing of single-crystalline III-V's on amorphous substrates, thus further expanding their utility for various applications. The process utilizes templated liquid-phase crystal growth that results in user-tunable, patterned micro and nanostructures of single-crystalline III-V's of up to tens of micrometres in lateral dimensions. InP is chosen as a model material system owing to its technological importance. The patterned InP single crystals are configured as high-performance transistors and photodetectors directly on amorphous SiO2 growth substrates, with performance matching state-of-the-art epitaxially grown devices. The work presents an important advance towards universal integration of III-V's on application-specific substrates by direct growth.
RESUMO
Nanoscale antidot arrays were fabricated on a single-crystal microflake of topological insulator Bi2Te3. The introduction of antidot arrays significantly increased the resistance of the microflake, yet the temperature dependence of the resistance remains metallic. We observed that small oscillations that are periodic in magnetic field B appeared on top of the weak anti-localization magnetoresistance. Since the electron coherence length at low temperature becomes comparable to the feature size in our device, we argued that the magnetoresistance oscillations are the manifestation of quantum interference induced by the nanostructure. Our work demonstrates that the transport of topological insulators could indeed be controlled by artificially created nanostructures, and paves the way for future technological applications of this class of materials.
