Performance optimization of (InxGa1-xN QWs/GaN LQB) structures for vertical-cavity surface-emitting lasers

IF 3.6 3区物理与天体物理 Q2 OPTICS

Journal of Luminescence Pub Date : 2025-09-03 DOI:10.1016/j.jlumin.2025.121512

Hameed Ur Rehman , Wengang Bi , Fang Wang , Yuhuai Liu

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引用次数: 0

Abstract

GaN-based Vertical-Cavity Surface-Emitting Lasers (VCSELs) are widely used, but electron leakage in multiple-quantum-wells (MQWs) and poor hole injection-reduce carrier density, leading to lower radiative recombination and higher threshold currents. This work investigates the coupled effects of InGaN/GaN MQWs, the last quantum barrier (LQB), and composition-graded electron blocking layers (EBLs) on VCSEL performance. Increasing the In content from 28 % to 30 % and reducing QW thickness enhances conduction and valence band offsets, reducing electron escape and improving electron-hole recombination at 415 nm. Incorporating a composition-graded Al _0.30-0.25Ga _0.70-0.75N EBL with a thinner LQB lowers the effective valence band barrier, improving hole injection into the MQWs. These combined effects significantly increase hole concentration within the MQWs, enhancing overall device performance. Finally, a 12.6 % increase in the stimulated recombination rate, a lower threshold current of 6.8 mA vs. 7.5 mA, an improved output power of 0.81 mW vs. 0.75 mW, and a reduced threshold voltage (Vth) of 4.6 V vs. 4.8 V are demonstrated for the optimized design (Str-C) due to the optimized synergy among the MQWs, LQB, and the composition-graded EBL.

Abstract Image

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垂直腔面发射激光器（InxGa1-xN QWs/GaN LQB）结构的性能优化

基于gan的垂直腔面发射激光器（VCSELs）应用广泛，但多量子阱（MQWs）中的电子泄漏和空穴注入不良会降低载流子密度，导致辐射复合较低和阈值电流较高。本研究研究了InGaN/GaN mqw、最后一个量子势垒（LQB）和成分梯度电子阻挡层（EBLs）对VCSEL性能的耦合影响。将In含量从28%增加到30%，并减小量子阱厚度，可以增强415 nm处的导电性和价带偏移，减少电子逸出，改善电子-空穴复合。将成分分级的Al 0.30-0.25Ga 0.70-0.75N EBL与更薄的LQB结合，降低了有效价带势垒，改善了mqw的孔注入。这些综合效应显著增加了mqw内的空穴浓度，从而提高了器件的整体性能。最后，由于mqw、LQB和成分分级EBL之间的优化协同作用，优化设计（strc）表明，受激复合率提高了12.6%，阈值电流较低，分别为6.8 mA和7.5 mA，输出功率提高了0.81 mW和0.75 mW，阈值电压（Vth）降低了4.6 V和4.8 V。

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来源期刊

Journal of Luminescence 物理-光学

CiteScore

6.70

自引率

13.90%

发文量

850

审稿时长

3.8 months

期刊介绍： The purpose of the Journal of Luminescence is to provide a means of communication between scientists in different disciplines who share a common interest in the electronic excited states of molecular, ionic and covalent systems, whether crystalline, amorphous, or liquid. We invite original papers and reviews on such subjects as: exciton and polariton dynamics, dynamics of localized excited states, energy and charge transport in ordered and disordered systems, radiative and non-radiative recombination, relaxation processes, vibronic interactions in electronic excited states, photochemistry in condensed systems, excited state resonance, double resonance, spin dynamics, selective excitation spectroscopy, hole burning, coherent processes in excited states, (e.g. coherent optical transients, photon echoes, transient gratings), multiphoton processes, optical bistability, photochromism, and new techniques for the study of excited states. This list is not intended to be exhaustive. Papers in the traditional areas of optical spectroscopy (absorption, MCD, luminescence, Raman scattering) are welcome. Papers on applications (phosphors, scintillators, electro- and cathodo-luminescence, radiography, bioimaging, solar energy, energy conversion, etc.) are also welcome if they present results of scientific, rather than only technological interest. However, papers containing purely theoretical results, not related to phenomena in the excited states, as well as papers using luminescence spectroscopy to perform routine analytical chemistry or biochemistry procedures, are outside the scope of the journal. Some exceptions will be possible at the discretion of the editors.