Abstract
The formation mechanism of SiGe nanorod (NR) arrays fabricated by combining nanosphere lithography and Au-assisted chemical etching has been investigated. By precisely controlling the etching rate and time, the lengths of SiGe NRs can be tuned from 300 nm to 1 μm. The morphologies of SiGe NRs were found to change dramatically by varying the etching temperatures. We propose a mechanism involving a locally temperature-sensitive redox reaction to explain this strong temperature dependence of the morphologies of SiGe NRs. At a lower etching temperature, both corrosion reaction and Au-assisted etching process were kinetically impeded, whereas at a higher temperature, Au-assisted anisotropic etching dominated the formation of SiGe NRs. With transmission electron microscopy and scanning electron microscopy analyses, this study provides a beneficial scheme to design and fabricate low-dimensional SiGe-based nanostructures for possible applications.
Highlights
Over the past few decades, intensive research efforts have been devoted to the fabrication and characterization of Si-based nanostructures due to their intrinsic physical properties, high packing density, and compatibility with current Si technology [1]
By increasing the etching temperature to 20°C and 25°C, the etched SiGe nanostructures became apparently longer, i.e., the formation of SiGe NRs. These results demonstrated that the morphologies of etched SiGe nanostructures are strongly influenced by the etching temperatures and potentially can be controlled by varying other etching conditions
It is well known that metal-assisted chemical etching in the H2O2/HF solution may occur as a localized electrochemical process, with the nanometer-sized metal acting as a local cathode and microscopically local Si acting as an anode [17]
Summary
Over the past few decades, intensive research efforts have been devoted to the fabrication and characterization of Si-based nanostructures due to their intrinsic physical properties, high packing density, and compatibility with current Si technology [1]. All SiGe heterostructures used in this study were grown at 550°C in a multi-wafer ultra-high vacuum chemical vapor deposition (UHV/CVD) system. In this step, the PS nanospheres with a reduced size formed non-closely packed arrays on the surface.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
