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Solar-blind ultraviolet DBR (distributed bragg reflector) and preparation method thereof

A sun-blind zone and component gradual change technology, applied in the field of sun-blind ultraviolet DBR and its preparation, can solve the problems of lattice mismatch, difficulty in ensuring a flat and steep interface, large refractive index, etc., and achieve the goal of solving defects or cracking problems Effect

Active Publication Date: 2013-11-20
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the DBR structure whose high reflection area falls in the sun-blind ultraviolet region is rarely studied due to the difficulty in material preparation. An AlGaN alloy with an Al composition at least greater than 0.5, and the difference in refractive index between the two alloys should be as large as possible, and the large difference in refractive index means that the difference in Al composition of the two AlGaN alloys that make up the DBR structure should be As large as possible, but the greater the difference in Al composition, the greater the lattice mismatch between the two materials. Even a single-layer AlGaN alloy with high Al composition is difficult to prepare, and it is necessary to use two kinds of lattice mismatch. It is more difficult to obtain DBR periodic structure with high crystal quality and flat and steep interface in AlGaN materials with high Al composition
[0003] Doping In elements of appropriate composition into AlN or AlGaN can solve the above-mentioned lattice mismatch problem between the two layers of AlGaN, but with the increase of In composition, the growth temperature difference between AlInN and AlGaN becomes more and more Large, it will lead to phase separation of AlInN alloy and uneven In composition, and when AlInN grows on AlGaN, the composition transition layer is easy to appear during the actual growth, and it is difficult to ensure a flat and steep interface

Method used

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  • Solar-blind ultraviolet DBR (distributed bragg reflector) and preparation method thereof
  • Solar-blind ultraviolet DBR (distributed bragg reflector) and preparation method thereof
  • Solar-blind ultraviolet DBR (distributed bragg reflector) and preparation method thereof

Examples

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Embodiment 1

[0031] The preparation method of the sun-blind ultraviolet DBR, the steps are:

[0032] (1) Deposit 900nm thick Al on the sapphire substrate by MOCVD method 0.5 Ga 0.5 N thin film serves as a growth template for the DBR structure;

[0033] (2) Deposit a layer of 29nm thick Al 0.74 In 0.01 Ga 0.25 N-Al 0.84 In 0.01 Ga 0.15 N-component graded layer is used as the first λ / 4 layer of DBR, λ=274nm;

[0034] (3) in Al 0.84 In 0.01 Ga 0.15 11nm Al grown on N 0.98 In 0.02 N layer and 16nm Al 0.5 Ga 0.5 The N layers together constitute the second λ / 4 layer of DBR, and the second λ / 4 layer and the first λ / 4 layer constitute a complete cycle of DBR;

[0035] (4) Continue to deposit the remaining 19 periods on the first period of the DBR to form a 20-period DBR structure.

[0036] The scanning electron microscope photo of the sun-blind ultraviolet DBR sample grown in this example based on AlInGaN / AlInN / AlGaN three-layer 20-period structure is shown in figure 2 . The sim...

Embodiment 2

[0038] The steps of this embodiment are basically the same as those of Comparative Example 1, the difference being that the number of cycles of the DBR structure is 38.

[0039] The simulation calculation results of the DBR structure reflectance spectrum in this embodiment are as follows Figure 5 As shown, the reflectance at the central wavelength of 274nm is 99%;

Embodiment 3

[0041] The steps of this embodiment are basically the same as those of Comparative Example 1, the difference being that the period number of the DBR structure is 10, and the Al 0.5 Ga 0.5 N layer thickness d 1 500nm.

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Abstract

The invention discloses an AlInGaN-based solar-blind ultraviolet DBR with three periodic structures. The AlInGaN-based solar-blind ultraviolet DBR with the three periodic structures structurally and sequentially comprises a sapphire substrate, an Al0.5 Ga0.5N template layer with a d1 thickness, and a DBR periodic layer from bottom to top, wherein the DBR periodic layer comprises n periods, and each period comprises structures from bottom to up as follows: an AlxlInylGal-xl-ylN-Alx2Iny2Gal-x2-y2N component gradient layer with a d2 thickness, an Alx3Inl-x3N layer with a d3 thickness and an Alx4Gal-x4N layer with a d4 thickness. According to the AlInGaN-based solar-blind ultraviolet DBR with the three periodic structures, In components are added, so that lattice mismatch degrees among the layers can be reduced; and meanwhile, the component gradient layer facilitates epitaxial growth of the AlInN layer, the application of the A10.5Ga0.5N template layer further facilitates epitaxial growth of the component gradient layer, and the defect or the cracking problem caused by deformation accumulated by lattice mismatch can be solved.

Description

technical field [0001] The patent of the present invention relates to the field of optoelectronic devices, in particular to a sun-blind ultraviolet DBR based on an AlInGaN three-layer periodic structure and a preparation method thereof. Background technique [0002] Bragg reflector (DBR) is an important part of microcavity devices, and plays an important role in the field of optoelectronic devices such as vertical cavity surface emitting lasers, resonant cavity light emitting diodes and resonant cavity enhanced detectors. There are many DBR structure materials that can be used in the visible light to infrared range in the high reflection area, such as GaAs-based, InP-based, InAs-based materials, SiO2 / SiN dielectric materials, organic compound materials, etc. DBRs in these wavelength ranges have been widely used. Recently, the wide-bandgap group III nitride materials have been developed rapidly, and ultraviolet, blue, and green light-emitting diodes and blue and green lasers ...

Claims

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Application Information

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IPC IPC(8): H01L33/10H01L33/00H01S5/183
Inventor 陈敦军张荣郑有炓
Owner NANJING UNIV