An InGaN/GaN multiple quantum well structure with strain modulation structure

Abstract

The invention relates to the field of group III nitride semiconductor optoelectronic materials, An InGaN / GaN multiple quantum well structure with strain modulation structure is proposed, include an underbarrier layer, a top barrier layer, a plurality of InGaN quantum well layers located between the bottom barrier layer and the top barrier layer, and an intermediate barrier layer disposed between the respective InGaN quantum well layers, characterized by, A first strain reduction layer immediately adjacent to and disposed beneath the InGaN quantum well layer is also included, and a second strain reduction layer disposed immediately adjacent to and above the InGaN quantum well layer, The first strain reduction layer and the second strain reduction layer are InGaN layers having an In component of less than 10%, and the intermediate barrier layer comprises a strain compensation layer having a lattice constant smaller than that of the bottom barrier layer and the top barrier layer. The invention provides a novel active region structure for improving the efficiency of a GaN-based blue-green LED and a laser.

Description

technical field [0001] The invention relates to the field of Group III nitride semiconductor optoelectronic materials, in particular to an InGaN / GaN multi-quantum well structure containing a strain modulation structure. Background technique [0002] The invention of quantum well is a major breakthrough with milestone significance in the history of semiconductor material development. The concept of quantum wells began in 1963 with the double heterojunction proposed by Alferov and Cromer. Then, in 1970, using this double heterostructure, the first semiconductor laser with continuous emission at room temperature came out. In the same year, Jiang Qi and Zhu Zhaoxiang proposed the concept of superlattice. They imagined that if two kinds of materials with good lattice matching are used to alternately grow periodic structures, and the thickness of each layer of material is below 100nm, the movement of electrons along the growth direction Oscillations will be generated, which can b...

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Problems solved by technology

However, InGaN / GaN quantum wells also have inherent limitations. When the luminescent wavelength moves to the long wavelength direction, as the In composition increases, the lattice mismatch between the InGaN well layer and the GaN barrier layer increases rapidly. InGaN The rapid increase of compressive strain in the well layer leads to a strong polarization effect in the well layer and a large number of misfit dislocations

The strong polarization effect makes the energy bands of quantum wells inclined, and the wave functions of electrons and holes are separated in space, resulting in a significant decrease in the efficiency of radiative recombination, and a large number of misfit dislocations means a large number of non-radiative recombination centers

Strong polarization effects and high dislocation density greatly limit the improvement of quantum efficiency in InGaN / GaN multiple quantum wells, which also limits the performance improvement of GaN-based LEDs and lasers

In addition, the stress in the quantum well layer will pass through the GaN barrier layer upwards, causing the internal stress in the InGaN well layer to increase layer by layer, resulting in a further increase in the polarization effect and dislocation density

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