CN-119811983-B - Conical medium array InGaN quantum dot structure and preparation method thereof

Abstract

The invention discloses a conical medium array InGaN quantum dot structure and a preparation method thereof, wherein the conical medium array InGaN quantum dot structure comprises a substrate, a GaN template layer, a conical medium array layer, a first InGaN quantum dot layer, a first GaN barrier layer, a second InGaN quantum dot layer and a second GaN barrier layer; the GaN template layer grows on the substrate, the conical medium array layer grows on the GaN template layer, the first InGaN quantum dot layer grows on the GaN template layer, the first GaN barrier layer grows uniformly and completely covers the first InGaN quantum dot layer, the second InGaN quantum dot layer grows on the first GaN barrier layer, the second GaN barrier layer grows uniformly and completely covers the second InGaN quantum dot layer, and a plurality of InGaN quantum dot layers and GaN barrier layers which are arranged periodically are repeatedly grown on the second GaN barrier layer in sequence to form a multi-layer InGaN quantum dot structure. The invention can realize the accurate adjustment of the density, the size, the distribution and the like of the quantum dots, and the grown InGaN quantum dots have the advantages of simple process and high crystal quality.

Inventors

• LIU WEI
• WANG DI
• YAN CHENGRUI
• LIU ZEYU
• ZHANG YAO
• SONG YIFAN

Assignees

• 西北工业大学

Dates

Publication Date

20260505

Application Date

20241225

Claims (6)

1. 1. The conical medium array InGaN quantum dot structure is characterized by comprising a substrate, a GaN template layer, a conical medium array layer, a first InGaN quantum dot layer, a first GaN barrier layer, a second InGaN quantum dot layer and a second GaN barrier layer; The GaN template layer grows on the substrate; the conical medium array layer grows on the GaN template layer; The first InGaN quantum dot layer is grown on the first GaN template layer, and all the first InGaN quantum dot layer is epitaxially grown in a spacing area between the conical medium array units in the conical medium array layer and does not grow on the surfaces of the conical medium array units; The first GaN barrier layer grows uniformly and completely covers the first InGaN quantum dot layer; The second InGaN quantum dot layer grows on the first GaN barrier layer; The second GaN barrier layer grows uniformly and completely covers the second InGaN quantum dot layer; a plurality of InGaN quantum dot layers and GaN barrier layers which are arranged periodically are repeatedly grown on the second GaN barrier layer in sequence to form a multi-layer InGaN quantum dot structure; the array units in the conical medium array layer are uniformly distributed in a nanoscale scale formed by adopting electron beam exposure, nanoimprint or self-aligned multiple exposure technology, and the conical medium array layer is of a conical or pyramidal structure with sharp top and smooth inclined side wall formed by using an undercut technology of an isotropic etching technology; the tapered dielectric array layer is formed of a silicon oxide, silicon nitride, hafnium oxide or aluminum oxide insulating dielectric material.
2. 2. The InGaN quantum dot structure of claim 1, wherein the lateral dimensions and distribution of the quantum dots of the first InGaN quantum dot layer are controlled by the tapered dielectric array layer.
3. 3. The InGaN quantum dot structure of claim 1, wherein the substrate is sapphire, silicon carbide, gallium nitride or gallium arsenide.
4. 4. The conical dielectric array InGaN quantum dot structure of claim 1, wherein the height of the dielectric array elements in the conical dielectric array layer is greater than the height of the quantum dots in the first InGaN quantum dot layer, the thickness of the first GaN barrier layer is greater than the height of the array elements in the conical dielectric layer, and the thickness of the second GaN barrier layer is greater than the height of the quantum dots in the second InGaN quantum dot layer.
5. 5. The InGaN quantum dot structure of claim 1 wherein the multi-layer InGaN quantum dot structure is consistent with the distribution of quantum dots in the first InGaN quantum dot layer under the influence of stress coupling to form a multi-layer self-aligned structure.
6. 6. The method for preparing the conical medium array InGaN quantum dot structure according to claim 1, comprising the following steps: Step 1, taking a substrate, wherein the substrate is made of sapphire, silicon carbide, gallium nitride or gallium arsenide, performing high-temperature cleaning treatment on the substrate in a hydrogen atmosphere at 1000-1200 ℃ for 5-20min, and then performing nitriding treatment; Step 2, growing a GaN template layer on the substrate; Step 3, depositing an insulating medium material on the GaN template layer, and forming a conical medium array layer with a uniform array with nanoscale dimensions by utilizing electron beam exposure, nanoimprint lithography or self-aligned multiple exposure micro-nano processing technology and combining an undercut technology of an isotropic etching technology; step 4, epitaxially growing InGaN quantum dot materials at the gap positions of the medium array units of the conical medium array layer to form a first InGaN quantum dot layer; Step 5, growing a first GaN barrier layer to cover the first InGaN quantum dot layer and the conical medium array layer; step 6, growing a second InGaN quantum dot layer on the first GaN barrier layer, and forming an InGaN quantum dot layer with a self-aligned structure by utilizing stress coupling action; Step 7, growing a second GaN barrier layer to cover the second InGaN quantum dot layer; And 8, sequentially and repeatedly growing an InGaN quantum dot layer and a GaN barrier layer with a plurality of periods on the second GaN barrier layer to finish the growth of the self-aligned multi-layer InGaN quantum dot.

Description

Conical medium array InGaN quantum dot structure and preparation method thereof Technical Field The invention belongs to the technical field of semiconductor materials, and particularly relates to a conical medium array InGaN quantum dot structure and a preparation method thereof. Background In recent years, the preparation technology of GaN-based semiconductor materials has been significantly advanced, and the rapid development of photoelectric devices such as Light Emitting Diodes (LEDs) and Laser Diodes (LDs) in the fields of display, illumination, etc. has been greatly promoted. However, conventional GaN-based light emitting devices generally employ a polar-plane grown InGaN/GaN multiple quantum well structure as an active region. Although the polar surface is grown with higher material quality, the Quantum Confinement Stark Effect (QCSE) induced by the strong built-in electric field causes the electrons and holes in the quantum well to be spatially separated, resulting in reduced radiative recombination efficiency. In addition, gaN-based materials generally have a disadvantage of high dislocation density, thereby further affecting the improvement of the luminous efficiency of the device. In order to overcome the problems, the InGaN quantum dot material with a three-dimensional limiting structure can effectively inhibit the QSE effect and shield dislocation, and becomes a research hot spot in the current GaN-based luminescent material field. However, the traditional InGaN quantum dot is prepared based on a self-assembly S-K growth mode, so that the randomness is high, and the obtained quantum dot has the problems of uneven distribution, poor size consistency and the like, so that the improvement of the material performance of the quantum dot is restricted. In order to improve the uniformity of InGaN quantum dots, researchers propose to adopt a selective area growth technology, etch a window area which is orderly arranged and regular in shape, and then perform epitaxial growth of InGaN to form the quantum dots with uniform distribution. However, after the growth of the InGaN quantum dot layer is completed, the method also needs to etch and remove redundant InGaN materials except for the window area, which results in complicating the whole preparation process, and damage to the InGaN quantum dot may be caused in the etching process, which is not beneficial to the preparation of high-quality InGaN quantum dot materials. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a conical medium array InGaN quantum dot structure and a preparation method thereof, wherein the conical medium array InGaN quantum dot structure comprises a substrate, a GaN template layer, a conical medium array layer, a first InGaN quantum dot layer, a first GaN barrier layer, a second InGaN quantum dot layer and a second GaN barrier layer; the GaN template layer grows on the substrate, the conical medium array layer grows on the GaN template layer, the first InGaN quantum dot layer grows on the GaN template layer, the first GaN barrier layer grows uniformly and completely covers the first InGaN quantum dot layer, the second InGaN quantum dot layer grows on the first GaN barrier layer, the second GaN barrier layer grows uniformly and completely covers the second InGaN quantum dot layer, and a plurality of InGaN quantum dot layers and GaN barrier layers which are arranged periodically are repeatedly grown on the second GaN barrier layer in sequence to form a multi-layer InGaN quantum dot structure. The invention can realize the accurate adjustment of the density, the size, the distribution and the like of the quantum dots, and the grown InGaN quantum dots have the advantages of simple process and high crystal quality. The technical scheme adopted for solving the technical problems is as follows: A conical medium array InGaN quantum dot structure comprises a substrate, a GaN template layer, a conical medium array layer, a first InGaN quantum dot layer, a first GaN barrier layer, a second InGaN quantum dot layer and a second GaN barrier layer; The GaN template layer grows on the substrate; the conical medium array layer grows on the GaN template layer; the first InGaN quantum dot layer grows on the first GaN template layer; The first GaN barrier layer grows uniformly and completely covers the first InGaN quantum dot layer; The second InGaN quantum dot layer grows on the first GaN barrier layer; The second GaN barrier layer grows uniformly and completely covers the second InGaN quantum dot layer; and the plurality of InGaN quantum dot layers and the GaN barrier layers which are arranged periodically are repeatedly grown on the second GaN barrier layer in sequence to form a multi-layer InGaN quantum dot structure. Preferably, the lateral size, density and distribution of the quantum dots of the first InGaN quantum dot layer are regulated by the tapered dielectric array layer, i.e. only the spacin