GaN-based monolithic integrated white light LED based on Van der Waals epitaxy and preparation method of GaN-based monolithic integrated white light LED

Abstract

The invention provides a GaN-based monolithic integrated white light LED based on Van der Waals epitaxy, and belongs to the technical field of semiconductors and illumination. The GaN-based monolithicintegrated white light LED sequentially comprises a substrate, a first graphene layer, an alN or GaN layer, an n-GaN layer, an In<x>Ga<1-x> N / GaN multi-quantum well, a first i-GaN layer, a second graphene layer, a second i-GaN layer, an In<y>Ga<1-y>N / GaN multi-quantum well, a third i-GaN layer, a third graphene layer, a fourth i-GaN layer, an In<z>Ga<1-z>N / GaN multi-quantum well, a fifth i-GaN layer and a p-GaN layer from bottom to top, and further comprises an n-type GaN ohmic contact electrode and a p-type GaN ohmic contact electrode. The invention further provides a preparation method of the GaN-based monolithic integrated white light LED based on Van der Waals epitaxy. According to the preparation method, graphene is used as a buffer layer between multiple quantum well layers, interlayer stress is regulated and controlled by utilizing the characteristic that Van der Waals' force exists between the graphene material layers, the problem of large lattice mismatch degree of each layeris solved, then an epitaxial layer with low strain degree and low dislocation density is obtained, finally, the white light LED device with high quality and high integration degree is obtained, the preparation process is simple, the effect is remarkable, and the application prospect is wide.

Description

technical field [0001] The invention relates to the fields of semiconductor technology and lighting technology, in particular to a GaN-based monolithic integrated white light LED based on van der Waals epitaxy and a preparation method thereof. Background technique [0002] At present, with the continuous improvement of the epitaxial technology of the GaN-based material system, the performance of high-brightness green light, blue light and shorter wavelength light-emitting diodes has made rapid progress. As an option for solid-state lighting in the future, light-emitting diodes have many advantages such as low power consumption, long life, and no pollution. So far, commercialized visible light-emitting diodes have covered the range from red to ultraviolet. [0003] With the continuous improvement of the luminous efficiency of LEDs, the luminous efficiency of commercialized white LEDs has reached or even exceeded the level of fluorescent lamps, and with technological innovati...

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Problems solved by technology

[0005] A type of white light diode that does not require long-wavelength phosphors mainly emits light through dual-color diodes or three-color diodes at the same time, and the color lights are mixed to emit white light. This type of diode contains many types, but most of them have many problems, such as: Donor Acceptor co-doped white LED, but the optical quality of this LED will drop sharply under the condition of strong current; photon cycle LED, this structure is to grow AlGaInP epitaxial wafer on the InP substrate, because the InP substrate is relatively fragile, so The yield rate is very low; the multi-quantum well structure white light LED distributed laterally, but this kind of process is very complicated and the manufacturing cost is extremely high, which is not conducive to mass production

[0006] The process of epitaxially two InGaN / GaN multi-quantum wells on the same sapphire substrate has also appeared on the market. This process has simple steps, but due to the large lattice mismatch between layers, the stress is too large. , a large distortion will be accumulated inside the device, which will cause the light peak position of the LED to change, causing the LED color rendering index and color temperature of this structure to be unsatisfactory; at the same time, it will also cause a large density of defects inside the device, These defects will become non-radiative recombination centers, which will reduce the performance and service life of LED devices

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