Startified thermal degradation in blue InGaN quantum well structures: P-GaN growth temperature and its influence on quantum well optical properties

The redistribution and segregation behavior of indium atoms in InGaN multiple quantum wells (MQWs) have been observed during the thermal annealing process in a vertical cavity surface emitting laser (VCSEL) structure. The migration of indium atoms may lead to a thermal degradation of InGaN/(In)GaN MQWs, resulting in the decomposition of InGaN QW and quantum barrier (QB) layers as well as the broadening of QW layers. Photoluminescence (PL) mapping measurements indicate that indium aggregation occurs in QWs without protection, which will cause the inhomogeneous luminescence of the MQW and decrease the laser optical performance. Temperature-dependent and excitation power-dependent PL spectra were employed to examine the presence of nonradiative recombination centers in deep localized states formed by indium aggregation, which also deteriorate the luminescence performance. Furthermore, a protective structure containing an InGaN or GaN sacrifice layer is proposed to suppress thermal degradation and improve the luminescence performance.

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Effects of TMIn flow rate during quantum barrier growth on multi-quantum well material properties and device performance of GaN-based laser diodes

Chen 陈,

Zhao 赵,

Liang 梁

et al. 2024

Chinese Phys. B

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Multidimensional influence of indium composition in barrier layers on GaN-based blue laser diodes (LDs) are discussed through both material quality and device physics perspectives. LDs with higher indium content in the barriers demonstrate a notably lower threshold current and shorter lasing wavelength compared to those with lower indium content. Our experiments reveal that higher indium content in the barrier layers can partially reduce indium composition in the quantum wells, a novel discovery. Employing higher indium content barrier layers leads to improved luminescence properties of MQW region. Detailed analysis reveals that this improvement can be attributed to better homogeneity in the indium composition of the well layers along the epitaxy direction. InGaN barrier layers suppressed lattice mismatch between barrier and well layers, thus mitigating the indium content pulling effect in well layers. In supplement to experimental analysis, theoretical computations are performed, showing that InGaN barrier structures can effectively enhance carrier recombination efficiency and optical confinement of LD structure, thus improving output efficiency of GaN-based blue LDs. Combining these theoretical insights with our experimental data, we propose that higher indium content barriers effectively enhance carrier recombination efficiency and indium content homogeneity in quantum well layers, thereby improving the output performance of GaN-based blue LDs.

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Startified thermal degradation in blue InGaN quantum well structures: P-GaN growth temperature and its influence on quantum well optical properties

Cited by 5 publications

References 39 publications

1D metal nitrides-based heterojunctions as efficient photoanodes for photoelectrochemical water splitting

1D metal nitrides-based heterojunctions as efficient photoanodes for photoelectrochemical water splitting

Mechanism of Indium Redistribution and Thermal Degradation in InGaN/(In)GaN Quantum Wells of Vertical Cavity Surface Emitting Lasers

Effects of TMIn flow rate during quantum barrier growth on multi-quantum well material properties and device performance of GaN-based laser diodes

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