Method for growing gaas nanowires on si substrate

Abstract

The invention discloses a method for growing GaAs nanowires on a Si substrate, comprising the following steps: (1) selecting a substrate and crystal orientation: selecting Si (111) as the substrate; (2) cleaning and re-oxidizing the surface of the substrate; (3) Substrate annealing treatment: put the substrate into the reaction chamber, and anneal the treated Si substrate at 690-720°C for 10-15 minutes; (4) Preparation of GaAs nanowires: use molecular beam The epitaxial growth process uses a two-step temperature method to grow GaAs nanowires on the Si substrate after the above treatment. The invention has the advantages of simple growth process, low preparation cost, and can grow GaAs nanowires with high density and good shape. At the same time, the GaAs nano wire crystal prepared by the invention has good quality, large specific surface area, no heterogeneous element impurities, and high luminous efficiency and light absorption rate.

Description

technical field [0001] The present invention relates to GaAs nanowires, in particular to a method for growing GaAs nanowires on Si substrates. Background technique [0002] In recent years, with the development of nanotechnology, one-dimensional nanostructures have attracted more and more attention. In this structure, the motion of the charge carriers is localized in one particular direction, and limited by potential barriers in the other two directions. This endows one-dimensional nanomaterials with properties that many three-dimensional materials do not possess. For example, the emission wavelength of the material can be modulated by the diameter of the nanowire. [0003] Due to its excellent properties such as high carrier mobility and direct band gap, the III-V compound GaAs has been combined with the traditional integrated circuit substrate material Si for decades. However, due to the large lattice mismatch between Si and GaAs, it is impossible to fabricate Si-GaAs he...

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Problems solved by technology

[0004] However, devices made of GaAs nanowires have not yet been commercialized

The reason is that although the shape and density of GaAs nanowires obtained by using gold nanoparticles as a catalyst are well controlled, gold atoms will diffuse into GaAs nanowires during the growth process, and deep impurity levels will be introduced into them, thereby greatly enhancing the non-magnetic properties of the GaAs nanowires. Radiative recombination, so that the performance of the device cannot meet the requirements

However, the selective growth method using a silicon dioxide template has the disadvantages of obtaining GaAs nanowires with more defects and complicated processes; while the nanowires grown by gallium autocatalysis do not have the above-mentioned problems, but are grown in the traditional single-step method. In the GaAs nanowire process, it is difficult to control the density and morphology of the nanowires separately

Because the use of lower growth temperature can significantly increase the nucleation density of nanowires, but it will strengthen the parasitic two-dimensional growth, and cannot obtain the required morphology; high growth temperature can reduce the parasitic growth and accelerate the growth rate; but it will It brings problems such as low density of nanowires and poor orientation

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