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V-Defect and Dislocation Analysis in InGaN Multiple Quantum Wells on Patterned Sapphire Substrate
摘要： InGaN/GaN multiquantum well (MQW) structures have been grown on cone-shaped patterned sapphire substrates (CPSS) by metalorganic chemical vapor deposition (MOCVD). From the transmission electron microscopy (TEM) results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the slant region of the cone pattern, they converged at the slope of the cone patterned region by staircase-upward propagation, which seems to effectively prevent TDs from vertical propagation in the trench region. The associated dislocation runs up into the overgrown GaN layer and MQW, and some (a+c) dislocations were shown to decompose inside the multi-quantum well, giving rise to a misfit segment in the c-plane and a V-shape defect. From cross-sectional TEM, we found that all V defects are not always connected with TDs at their bottom, some V defects are generated from the stacking mismatch boundaries induced by stacking faults which are formed within the MQW due to the strain relaxation.
关键词： V defects,Transmission electron microscopy (TEM),InGaN multi-quantum well (MQW),Threading dislocations (TDs)
更新于2025-09-23 15:22:29
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[IEEE 2018 12th International Conference on Advanced Semiconductor Devices and Microsystems (ASDAM) - Smolenice (2018.10.21-2018.10.24)] 2018 12th International Conference on Advanced Semiconductor Devices and Microsystems (ASDAM) - Determination of Secondary-Ions Yield in SIMS Depth Profiling of Si, Mg, and C Ions Implanted Gan Epitaxial Layers
摘要： In this paper, we investigated the optical and electrical properties of InGaN/GaN multiple quantum well (MQW) structures grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD). The samples were characterized using photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), and Hall effect measurements. The results show that the In composition and well width significantly affect the emission wavelength and carrier concentration. The highest internal quantum efficiency (IQE) of 45% was achieved for the sample with 15% In and 3 nm well width at room temperature. These findings are crucial for the development of high-efficiency light-emitting diodes (LEDs) in the visible range.
关键词： MOCVD,MQW,LED,photoluminescence,InGaN
更新于2025-09-19 17:15:36
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Performance Enhancement of GeSn Transistor Laser with Symmetric and Asymmetric Multiple Quantum Well in the Base
摘要： The performance of a Multiple Quantum Well (MQW) Heterojunction Bipolar Transistor Laser (HBTL) has been studied using GeSn alloy. Both symmetric and asymmetric quantum wells have been considered. Main analysis is focused on finding the minority carrier concentration in the base, the base threshold current, light output power of the device and the values are compared with GeSn based Single Quantum Well and InGaAs based Multiple Quantum Well Transistor Laser.
关键词： HBTL,A-MQW,SQW,S-MQW
更新于2025-09-19 17:13:59
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Redefinition the quasi-Fermi energy levels separation of electrons and holes inside and outside quantum wells of GaN based multi-quantum-well semiconductor laser diodes
摘要： Both accurate experiments and a self-consistent theoretical simulation using the near-ABC or ab initio method have uncovered the anomalous changes in the junction voltage (Vj ) of GaN-based lasers (Li et al 2013 Appl. Phys. Lett. 102 123501, Feng et al 2018 J. Phys. D: Appl. Phys. 51 095102 and Feng et al Appl. Phys. B 124 39). Here, further accurate emission spectral characteristics and band-gap simulation of a GaN based laser diodes (LDs) confirmed that previous researchers may have confused the junction voltage (Vj ) and the separation between the two Fermi levels of electrons and holes in the active region divided by the electronic charge (ΔEf /e). For the multiple-quantum wells (MQWs), there are obvious differences between them. For an ideal GaN-based LDs, despite the increase in junction voltage, physical quantities including the separation between the two Fermi levels of electrons and holes in the MQW region, and the optical net gain remain unchanged beyond the threshold region after an unpredictable sharp increase in the threshold region.
关键词： multi-quantum-well (MQW),steady state,junction voltage,quasi-Fermi energy levels separation,GaN based laser diodes (LD)
更新于2025-09-19 17:13:59
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Polarization Diverse Photodetector Chip Based on Waveguide Integrated MQW and Bulk Photodiodes
摘要： A photodetector chip for polarization diverse detection is presented. Serially connected MQW and bulk photodiodes detect TE and TM light separately with responsivities of 0.65 A/W and 0.45 A/W, respectively. Detection of 2x25 GBaud for dual polarization signals with a BER of 10-6 is demonstrated.
关键词： Photodetector,MQW,Diverse,Polarization,Multi-Quantum-Well
更新于2025-09-16 10:30:52
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Performance Prediction of a Quantum Well Infrared Photodetector Using GeSn/SiGeSn Structure
摘要： QWIP using group IV elements have created more interest among researchers for its potential application in optical communication as well as in optical interconnects. This paper presents modeling and theoretical analysis of Sn-based tensile strained type I direct band gap QWIP in which the active region has a multiple quantum well structure formed with Ge0.92Sn0.08 quantum wells separated by Si0.11Ge0.7Sn0.19 barriers. The structure reported by V. Ryzhii et al. has been reproduced and the parameters like responsivity, power density and the dark current density have been analytically calculated. A comprehensive comparison of responsivity and power density of this proposed structure with the existing QWIP structure made of GaAs/InGaAs is reported here. An improvement in the field of responsivity is observed with the proposed model. The reduction of threshold power density corresponds to an effective operation of the QWIPs in incident infrared radiation. The intersubband electron transition and tunneling electron injection effects are considered here to predict a better performance of the proposed structure operated in infrared region.
关键词： QWIP,MQW,Infrared radiation,ISBT
更新于2025-09-11 14:15:04