InAs quantum material with low-density characteristic
Through the critical island formation method and oblique rotary-free substrate method combined with coupled quantum dot growth technology, multi-layer structure is used to grow InAs quantum dots, which solves the problem of low growth success rate of low-density InAs quantum dots in the existing technology, achieves the growth of high-quality and low-density quantum dots, and expands the luminescence wavelength to meet the density requirements of a single photon source.
Patent Information
- Application Number
- CN202421267122.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-05
- Publication Date
- 2025-02-28
- Estimated Expiration
- 2034-06-05
AI Technical Summary
The prior art is difficult to grow high-quality low-density InAs quantum dots, especially in the long wavelength range, and the growth success rate of low-density quantum dots is relatively low.
The critical island-forming method is used to combine the obliquely arranged rotary-free substrate method and coupled quantum dot growth technology, and the multi-layer structure of the GaAs buffer layer, the InAs sacrificial layer, the GaAs growth layer, the first and second growth coupled quantum dot seed layers and the GaAs cover layer, precise control and growth of low-density InAs quantum dots are achieved.
The success rate of low-density quantum dot growth is improved, the luminescence wavelength of quantum dots is expanded, and low-density controlled coupled quantum dots are obtained, meeting the density requirements of single-photon sources.
Smart Images
Figure CN222547951U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of quantum material preparation, in particular to an InAs quantum material with low-density characteristics. Background Art
[0002] At present, in the growth of low-density InAs quantum dots, (i) electron beam exposure and etching technology are used to etch patterns on the substrate as the nucleation position of the quantum dots to control the growth position and density of the quantum dots. However, due to defects and impurities introduced into the patterned substrate, it is difficult to grow quantum dots with good optical quality, and the precision and cleanliness of the process are very high. (ii) The gradient growth method is easy to find a suitable area along the gradient direction on a wafer due to the gradient distribution. The success rate of low-density quantum dot growth is very high, but the utilization rate of the grown quantum dots is not high, and only a small amount of quantum dots can be grown on a wafer. The density in an area is relatively appropriate; (iii) The line width of quantum dots grown by the droplet epitaxy-assisted growth method is very wide, and it is difficult to make a single-photon source; (iv) The critical islanding method is only suitable for the growth of short-wavelength quantum dots due to its small deposition amount. Compared with the InAs / GaAs quantum dot single-photon source with an emission wavelength below 1μm, the single-photon source with an emission wavelength of 1.3μm matches the optical signal transmission range and is more practical. However, due to the low sensitivity of the long-wavelength InGaAs detector, the single-photon source used in experiments is mainly concentrated below 1μm, and there is little research on low-density long-wavelength coupled quantum dots.
[0003] In summary, it is very necessary to propose an InAs quantum material that is easy to grow and has low-density characteristics. Utility Model Content
[0004] The utility model aims to provide an InAs quantum material with low-density characteristics, which is easy to produce and can obtain low-density controllably coupled quantum dots. The InAs quantum material has the luminescence characteristics of a single quantum dot.
[0005] To achieve the above-mentioned purpose, the utility model adopts an InAs quantum material with low-density characteristics, including a GaAs buffer layer, an InAs sacrificial layer, a GaAs growth layer, a first growth coupling quantum dot seed layer, a GaAs spacer layer, a second growth coupling point quantum dot seed layer and a GaAs capping layer, the InAs sacrificial layer is grown on the upper surface of the GaAs buffer layer, the GaAs growth layer is grown on the upper surface of the InAs sacrificial layer, the first growth coupling quantum dot seed layer is grown on the GaAs growth layer, the GaAs spacer layer is grown on the upper surface of the first growth coupling quantum dot seed layer, the second growth coupling point quantum dot seed layer is grown on the GaAs spacer layer, and the GaAs capping layer is grown on the upper surface of the second growth coupling quantum dot seed layer.
[0006] Wherein, the growth rate of the GaAs buffer layer is 1 μm / h and the thickness is 300 nm.
[0007] Wherein, the growth rate of the InAs sacrificial layer is 0.005 ML / s.
[0008] Wherein, the thickness of the GaAs growth layer is 50-100 nm.
[0009] Wherein, the growth rate of the first growth coupled quantum dot seed layer is 0.005 ML / s.
[0010] Wherein, the growth rate of the GaAs spacer layer is 1 μm / h, and the thickness is 10 nm.
[0011] Wherein, the growth rate of the second growth coupling point quantum dot seed layer is 0.1 ML / s.
[0012] Wherein, the thickness of the GaAs capping layer is 50 nm.
[0013] The utility model discloses an InAs quantum material with low-density characteristics. The critical island formation method is adopted to realize the precise control of the growth of low-density InAs quantum dots, thereby improving the success rate of the growth of low-density quantum dots. The inclined non-rotation substrate method and the coupled quantum dot growth technology are adopted, and the GaAs cover layer is combined to further extend the luminescent wavelength of the low-density quantum dots. The thickness between the quantum dot coupling layers is optimized by deposition below the critical amount and long-term pause, thereby obtaining low-density controllable coupled quantum dots with single quantum dot luminescence characteristics. The InAs quantum material with low-density characteristics is easy to produce. The controllable low-density quantum dots are formed by deposition below the critical amount and long-term pause as the first growth coupled quantum dot seed layer. By adjusting the thickness of the second growth coupled quantum dot seed layer and the first growth coupled quantum dot seed layer, low-density controllable coupled quantum dots can be obtained, which can meet the density requirement of the single-photon source. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0015] Figure 1 It is a schematic structural diagram of the InAs quantum material with low density characteristics of the utility model.
[0016] 10-GaAs buffer layer, 20-InAs sacrificial layer, 30-GaAs growth layer, 40-first growth coupling quantum dot seed layer, 50-GaAs spacer layer, 60-second growth coupling quantum dot seed layer, 70-GaAs capping layer. DETAILED DESCRIPTION
[0017] See also Figure 1 ,in Figure 1 It is a schematic diagram of the structure of InAs quantum material with low-density characteristics.
[0018] The utility model provides an InAs quantum material with low-density characteristics: comprising a GaAs buffer layer 10, an InAs sacrificial layer 20, a GaAs growth layer 30, a first growth coupling quantum dot seed layer 40, a GaAs spacer layer 50, a second growth coupling point quantum dot seed layer 60 and a GaAs capping layer 70, wherein the InAs sacrificial layer 20 is grown on the upper surface of the GaAs buffer layer 10, the GaAs growth layer 30 is grown on the upper surface of the InAs sacrificial layer 20, the first growth coupling quantum dot seed layer 40 is grown on the GaAs growth layer 30, the GaAs spacer layer 50 is grown on the upper surface of the first growth coupling quantum dot seed layer 40, the second growth coupling point quantum dot seed layer 60 is grown on the GaAs spacer layer 50, and the GaAs capping layer 70 is grown on the upper surface of the second growth coupling point quantum dot seed layer 60.
[0019] In this embodiment, the critical islanding method is used to achieve precise control of the growth of low-density InAs quantum dots, thereby improving the success rate of low-density quantum dot growth; the tilted non-rotating substrate method and the coupled quantum dot growth technology are used, combined with the GaAs capping layer 70, to further extend the luminescent wavelength of the low-density quantum dots; by depositing below the critical amount and pausing for a long time and then optimizing the thickness between the quantum dot coupling layers, low-density controllable coupled quantum dots are obtained, and the luminescent characteristics of single quantum dots are obtained; the InAs quantum material with low-density characteristics is easy to produce, and controllable low-density quantum dots are formed by depositing below the critical amount and pausing for a long time as the first growth coupled quantum dot seed layer 40, and by adjusting the thickness of the second growth coupled quantum dot seed layer 60 and the first growth coupled quantum dot seed layer 40, low-density controllable coupled quantum dots can be obtained, which can meet the density requirements of the single-photon source.
[0020] Furthermore, the growth rate of the GaAs buffer layer 10 is 1 μm / h, and the thickness is 300 nm.
[0021] Furthermore, the growth rate of the InAs sacrificial layer 20 is 0.005 ML / s.
[0022] Furthermore, the thickness of the GaAs growth layer 30 is 50-100 nm.
[0023] Furthermore, the growth rate of the first growth-coupled quantum dot seed layer 40 is 0.005 ML / s.
[0024] Furthermore, the growth rate of the GaAs spacer layer 50 is 1 μm / h, and the thickness is 10 nm.
[0025] Furthermore, the growth rate of the second growth coupling point quantum dot seed layer 60 is 0.1 ML / s.
[0026] Furthermore, the thickness of the GaAs capping layer 70 is 50 nm.
[0027] In this embodiment, the InAs sacrificial layer 20 is grown in situ to obtain the critical island formation condition of InAs quantum dots: the GaAs buffer layer 10300nm is grown at a rate of 1μm / h, and then the InAs sacrificial layer 20 is grown at a rate of 0.005ML / s at 560℃, with V / III being 30. In situ monitoring is performed by RHEED. When bright dot patterns appear on the RHEED image, the InAs deposition amount at this time is defined as the critical island formation thickness (θc). The temperature is then raised to 660℃ and maintained for 10 minutes for in-situ annealing, so that the deposited InAs sacrificial layer 20 is completely desorbed. The InAs introduced in the in-situ test has no effect on the InAs quantum dots in the active area.
[0028] After annealing, the temperature is lowered to 620°C to grow the GaAs growth layer 30 of 50-100nm, and then lowered to 560°C to grow the first growth coupled quantum dot seed layer 40 by a long pause method; the growth rate is 0.005ML / s, V / III is about 30, and the InAs deposition amount is θc-0.09ML, which is lower than the critical condition. After the growth is completed, the In baffle is closed, and the As beam and substrate temperature are maintained for 2 minutes to allow In atoms to have enough pause time to migrate and form extremely low density large-size quantum dots.
[0029] Grow the GaAs spacer layer 50 and perform in-situ annealing to eliminate defects: Grow the GaAs spacer layer 5010nm at a low temperature (quantum dot growth temperature 560°C) with a growth rate of 1μm / h, then raise the substrate temperature to 610-650°C and maintain in-situ annealing for 8 minutes with a heating rate of 30°C / min.
[0030] The second low-temperature and high-speed growth coupling point quantum dot seed layer 60: reduce the substrate temperature to 480-525°C, the growth rate is 0.1ML / s, pause for 10s after every 0.1ML growth, the total InAs deposition amount is 2ML, slightly larger than the critical island thickness of InAs quantum dots grown under low-temperature and high-speed conditions, about 1.9ML, and the surface is covered with 50nm of the GaAs covering layer 70.
[0031] The method of growing quantum dots by in-situ acquisition of critical growth parameters by sacrificial layer quantum dots and fine-tuning them has increased the repeatability of low-density quantum dot growth from 47% of the traditional critical islanding method to 80%; the method of growing gradient-distributed quantum dots without substrate deflection has been adopted, and the density distribution gradient of quantum dots is most suitable, and quantum dots with wavelengths of 900 to 960nm can be obtained in two different areas of the wafer. On this basis, improvements are made, combining coupled quantum dots and GaAs capping layers to increase the luminous wavelength of quantum dots and the success rate of low-density quantum dot growth; finally, by depositing below the critical amount and pausing for a long time to form controllable low-density quantum dots as the first layer in the coupled quantum dot structure, by adjusting the thickness of the first growth coupled quantum dot seed layer 40 and the second growth coupled quantum dot seed layer 60, low-density controllable coupled quantum dots can be obtained, which can meet the density requirements of single-photon sources.
[0032] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope covered by the utility model.
Claims
1. An InAs quantum material with low density characteristics, characterized in that: The invention comprises a GaAs buffer layer, an InAs sacrificial layer, a GaAs growth layer, a first growth coupled quantum dot seed layer, a GaAs spacer layer, a second growth coupled quantum dot seed layer and a GaAs capping layer, wherein the InAs sacrificial layer is grown on the upper surface of the GaAs buffer layer, the GaAs growth layer is grown on the upper surface of the InAs sacrificial layer, the first growth coupled quantum dot seed layer is grown on the GaAs growth layer, the GaAs spacer layer is grown on the upper surface of the first growth coupled quantum dot seed layer, the second growth coupled quantum dot seed layer is grown on the GaAs spacer layer, and the GaAs capping layer is grown on the upper surface of the second growth coupled quantum dot seed layer.
2. The InAs quantum material with low density characteristics according to claim 1, characterized in that: The growth rate of the GaAs buffer layer is 1 μm / h, and the thickness is 300 nm.
3. The InAs quantum material with low density characteristics according to claim 1, characterized in that: The growth rate of the InAs sacrificial layer is 0.005 ML / s.
4. The InAs quantum material with low density characteristics according to claim 1, characterized in that: The thickness of the GaAs growth layer is 50-100 nm.
5. The InAs quantum material with low density characteristics according to claim 1, characterized in that: The growth rate of the first growth coupled quantum dot seed layer is 0.005 ML / s.
6. The InAs quantum material with low density characteristics according to claim 1, characterized in that: The growth rate of the GaAs spacer layer is 1 μm / h, and the thickness is 10 nm.
7. The InAs quantum material with low density characteristics according to claim 1, characterized in that: The growth rate of the second growth coupling point quantum dot seed layer is 0.1 ML / s.
8. The InAs quantum material with low density characteristics according to claim 1, characterized in that: The thickness of the GaAs capping layer is 50 nm.