Selective area epitaxy of in-plane HgTe nanostructures on CdTe(001) substrate
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2024-09-26 |
| Journal | Nanotechnology |
| Authors | Nicolas Chaize, X. Baudry, PierreāHenri Jouneau, Erwan Gautier, JeanāLuc RouviĆØre |
| Institutions | Brown University, Centre National de la Recherche Scientifique |
| Citations | 1 |
Abstract
Section titled āAbstractāAbstract Semiconductor nanowires (NWs) are believed to play a crucial role for future applications in electronics, spintronics and quantum technologies. A potential candidate is HgTe but its sensitivity to nanofabrication processes restrain its development. A way to circumvent this obstacle is the selective area growth technique. Here, in-plane HgTe nanostructures are grown thanks to selective area molecular beam epitaxy on a semi-insulating CdTe substrate covered with a patterned SiO 2 mask. The shape of these nanostructures is defined by the in-plane orientation of the mask aperture along the <110>, <1 <mml:math xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā overflow=āscrollā> <mml:mrow> <mml:mrow> <mml:mover> <mml:mn>1</mml:mn> <mml:mo stretchy=āfalseā>ĀÆ</mml:mo> </mml:mover> </mml:mrow> </mml:mrow> </mml:math> 0>, or <100> direction, the deposited thickness, and the growth temperature (GT). Several micron long in-plane NWs can be achieved as well as more complex nanostructures such as networks, diamond structures or rings. A good selectivity is achieved with very little parasitic growth on the mask even for a GT as low as 140 Ā°C and growth rate up to 0.5 monolayer per second. For <110> oriented NWs, the center of the nanostructure exhibits a trapezoidal shape with {111}B facets and two grains on the sides, while <1 <mml:math xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā overflow=āscrollā> <mml:mrow> <mml:mrow> <mml:mover> <mml:mn>1</mml:mn> <mml:mo stretchy=āfalseā>ĀÆ</mml:mo> </mml:mover> </mml:mrow> </mml:mrow> </mml:math> 0> oriented NWs show {111}A facets with adatoms accumulation on the sides of the top surface. Transmission electron microscopy observations reveal a continuous epitaxial relation between the CdTe substrate and the HgTe NW. Measurements of the resistance with four-point scanning tunneling microscopy indicates a good electrical homogeneity along the main NW axis and a thermally activated transport. This growth method paves the way toward the fabrication of complex HgTe-based nanostructures for electronic transport measurements.