Method for preparing low-density and long-wavelength indium arsenide/gallium arsenide (InAs/GaAs) quantum dots

Abstract

The invention provides a method for preparing low-density and long-wavelength indium arsenide / gallium arsenide (InAs / GaAs) quantum dots. The method includes a first step of picking up a substrate, a second step of depositing and growing a buffer layer on the substrate, a third step of depositing and growing an InAs layer on the buffer layer, suspending deposition and growth when the InAs layer does not reach the critical thickness, a fourth step of annealing the substrate with the growing InAs layer, a fifth step of rising temperature of the substrate after annealing, a sixth step of growing the InAs layer through secondary deposition, a seventh step of depositing and growing a GaAs cover layer on the InAs layer which grows through the secondary deposition, and obtaining the low-density and long-wavelength InAs / GaAs quantum dot structure. The method can be used for preparing the low-density InAs / GaAs quantum dots with room temperature luminous long-wavelength longer than 1.3 micrometers.

Description

technical field [0001] The invention relates to the field of semiconductor materials and optoelectronic technology, in particular to a growth method of low-density, large-size, and long-wavelength quantum dots, in particular to a molecular beam epitaxy method for growing low-density, long-wavelength InAs quantum dots on a GaAs substrate. Background technique [0002] In recent years, with the development of high-quality self-organized quantum dot technology, the research of semiconductor quantum dots in quantum optics and quantum communication has attracted more and more people's interest. These quantum dots not only finally realize the three-dimensional confinement of the carriers, resulting in the carriers having discrete energy levels due to the quantization of energy in three dimensions, showing some energy level characteristics similar to the shell structure of atoms, but also Also native to solid systems, they can be tuned to produce photons with nonclassical statistic...

AI Technical Summary

Problems solved by technology

[0004] However, the size of quantum dots prepared under this condition is small and the emission wavelength is short, which cannot meet the requirements of 1.3 μm or 1.55 μm wavelength required for optical fiber communication.

[0005] At present, people have tried some methods to limit the number of excited quantum dots or filter out the emission of other quantum dots, such as placing a metal mask with submicron holes above the quantum dots to select the emission of some quantum dots below, but this The method requires high-precision lithography, and due to the diffraction at the metal hole, the extraction efficiency is limited when coupled with a single-mode fiber; and the external quantum efficiency is very low due to the lack of spatial confinement of the carriers.

[0006] In summary, it is very difficult to grow long-wavelength quantum dots with low density and satisfy the requirements of fiber-matched single-photon source

Because of this, there is currently no mature low-density quantum dot single-photon light source on the market

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