Gan-based monolithic integrated white light LED based on van der Waals epitaxy and its preparation method

Abstract

The invention provides a GaN-based monolithic integrated white light LED based on van der Waals epitaxy, which belongs to the field of semiconductor technology and lighting technology, and includes a substrate, a first graphene layer, an AlN or GaN layer, an n-GaN layer, and In x Ga 1‑x N / GaN multiple quantum wells, first i‑GaN layer, second graphene layer, second i‑GaN layer, In y Ga 1‑y N / GaN multiple quantum wells, third i‑GaN layer, third graphene layer, fourth i‑GaN layer, In z Ga 1‑z N / GaN multiple quantum well, fifth i-GaN layer, p-GaN layer; also includes n-type GaN ohmic contact electrode and p-type GaN ohmic contact electrode. The present invention also provides a method for preparing the above-mentioned GaN-based monolithic integrated white light LED based on van der Waals epitaxy, using graphene as a buffer layer between multi-quantum well layers, and using the characteristic of van der Waals force between graphene material layers to regulate interlayer stress, Improve the problem of large lattice mismatch of each layer, and then obtain an epitaxial layer with low strain and low dislocation density, and finally obtain a high-quality, highly integrated white light LED device. The preparation process is simple, the effect is remarkable, and the application prospect is broad.

Description

Technical field[0001]The present invention relates to semiconductor techniques and illumination techniques, and more particularly to Van Dehua epitaxial GaN-based GaN-based single-film integrated white light LEDs and their preparation methods.Background technique[0002]At present, as the epitaxial technique of the GaN-based material system is continuously advanced, the high-brightness of green light, blue light, and the performance of the shorter wavelength of the light-emitting diode have made a step-flying advancement. As a selection of future solid state lighting, the light emitting diode has many advantages such as low power, long life, no pollution. As of now, the commercially available visible optical wave paragraph light-emitting diode has covered from red light to the ultraviolet range.[0003]As the luminescence efficiency of the LED is increasing, commercial white LED luminous efficiency has even exceeded the level of fluorescent lamps, and with the technological innovation, ...

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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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