Monolithic integrated nitride light-emitting wavelength adjustable white light LED and preparation method thereof

Abstract

The invention relates to the technical field of semiconductors, in particular to a monolithic integrated nitride light-emitting wavelength adjustable white light LED and a preparation method thereof, and solves the problems that the color temperature and the color rendering index of a white light LED are difficult to precisely regulate and control, and the performance and the service life are low. The LED comprises three light-emitting units, one light-emitting unit comprises a first graphene layer, a nitride buffer layer, a doped n-GaN layer, a blue light InGaN / GaN multi-quantum well layer and a doped p-GaN layer which are sequentially arranged from bottom to top; one light-emitting unit comprises a second graphene layer, a first non-doped i-InGaN layer, a first doped n-InGaN layer, a green light InGaN / InGaN multi-quantum well layer and a first doped p-InGaN layer which are sequentially arranged from bottom to top; and the other light-emitting unit comprises a third graphene layer, a second non-doped i-InGaN layer, a second doped n-InGaN layer, a red light InGaN / InGaN multi-quantum well layer and a second doped p-InGaN layer which are sequentially arranged from bottom to top. The device quality, the integration level, the performance and the service life are improved, and the color temperature and the color rendering index can be controlled.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a monolithic integrated nitride white light LED with an adjustable emission wavelength and a preparation method. 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. At present, whether it is in the fields of solid-state lighting or laser display, higher requirements are placed on the quality of LED light sources. White LEDs will be the mainstream of solid-state lighting in the future. How to improve the color rendering index and color temperature of LEDs is the direction of efforts. [0003] At present, the solutions to realize white light-emitting diodes can be divided into two types from the perspective of whether long-wavelength phosphors are required. Among ...

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Problems solved by technology

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 light is mixed to emit white light. This type of diode contains many types, but most of them have many problems, such as: Donor receiving The main co-doped white LED, the optical quality of this LED will drop sharply under the condition of strong current; such as: 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 is very low; such as: white light LED with multi-quantum well structure distributed laterally, this kind of process is very complicated, the manufacturing cost is extremely high, and it is not conducive to mass production

[0004] There has been a process of epitaxially two or three InGaN / GaN multiple quantum wells on the same sapphire substrate. This process step is simple, but due to the large lattice mismatch between layers, it leads to excessive stress. Large, a large distortion will accumulate inside the device, causing 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

Moreover, these LEDs are generally in the form of diodes with multiple quantum wells connected in series, and it is difficult to effectively control the distribution of the injected current among the quantum wells, which in turn makes it difficult to effectively control the ratio of each wavelength in the mixed color light. Color index and other parameters are difficult to precisely control

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