Estimation of relative defect densities in InGaN laser diodes by induced absorption of photoexcited carriers

Kim, C S; Jang, Y. D.; Shin, Dong‐Myung; Kim, J H; Lee, Dong−Han; Choi, Yoon Ho; Noh, Min-Soo; Yee, Ki‐Ju

doi:10.1364/oe.18.027136

Cited by 7 publications

(5 citation statements)

References 21 publications

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“…In addition, there is a probability that some of the probe photons are absorbed by the trapped electrons, having a long lifetime, in the sub-bandgap states. This absorption induces a transition of the trapped electron into the upper conduction band states, 33 depicted as transition a 3 by superimposing a E−k diagram in Figure 1d; here, E t is the trap energy level. This probe-induced absorption leads to a gradual shift of negative Δα to a positive Δα at the GaN band edge.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Reduced Auger Coefficient through Efficient Carrier Capture and Improved Radiative Efficiency from the Broadband Optical Cavity: A Mechanism for Potential Droop Mitigation in InGaN/GaN LEDs

Aggarwal

Udai

Saha

et al. 2022

ACS Appl. Mater. Interfaces

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Efficiency droop at high carrier-injection regimes is a matter of concern in InGaN/GaN quantum-confined heterostructure-based light-emitting diodes (LEDs). Processes such as Shockley–Reed–Hall and Auger recombinations, electron–hole wavefunction separation from polarization charges, carrier leakage, and current crowding are identified as the primary contributors to efficiency droop. Auger recombination is a critical contributor owing to its cubic dependence on carrier density, which can not be circumvented using an advanced physical layout. Here, we demonstrate a potential solution through the positive effects from an optical cavity in suppressing the Auger recombination rate. Besides the phenomenon being fundamentally important, the advantages are technologically essential. The observations are manifested by the ultrafast transient absorption pump-probe spectroscopy performed on an InGaN/GaN-based multi-quantum well heterostructure with external DBR mirrors of varying optical confinement. The optical confinement modulates the nonlinear carrier and photon dynamics and alters the rate of dominant recombination mechanisms in the heterostructure. The carrier capture rate is observed to be increasing, and the polarization field is reducing in the presence of optical feedback. Reduced polarization increases the effective bandgap, resulting in the suppression of the Auger coefficient. Superluminescent behavior along with enhanced spectral purity in the emission spectra in presence of optical confinement is also demonstrated. The improvement is beyond the conventional Purcell effect observed for the quantum-confined systems.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Reduced Auger Coefficient through Efficient Carrier Capture and Improved Radiative Efficiency from the Broadband Optical Cavity: A Mechanism for Potential Droop Mitigation in InGaN/GaN LEDs

Aggarwal

Udai

Saha

et al. 2022

ACS Appl. Mater. Interfaces

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“…9,10 Defects can also introduce electronic traps (defect states) in the bandgap, which could affect the luminescence spectrum of a laser device. 10,11 Thus, a defect-free III-V buffer layer is crucial for the high performance of optoelectronic devices. It is particularly important to avoid anti-phase boundaries (APBs) in the III-V buffer layers, at which charge carriers can be trapped 12,13 and recombined by the formation of doubleatomic steps 14 on Ge(100) surfaces.…”

Section: ■ Introductionmentioning

confidence: 99%

“…An atomically abrupt and well-ordered III-V/Ge(100) heterointerface is the key to prevent crystalline defects originating from the heterointerface. Defects present in the III-V epitaxial layers commonly act as non-radiative recombination centers, which reduce photon emission efficiency. , Defects can also introduce electronic traps (defect states) in the bandgap, which could affect the luminescence spectrum of a laser device. , Thus, a defect-free III-V buffer layer is crucial for the high performance of optoelectronic devices. It is particularly important to avoid anti-phase boundaries (APBs) in the III-V buffer layers, at which charge carriers can be trapped , and recombined by the formation of double-atomic steps on Ge(100) surfaces.…”

Section: Introductionmentioning

confidence: 99%

Optical In Situ Studies of Ge(100) Interfacial Exchange Reactions in GaAs-Rich MOVPE Reactors for Low-Defect III-P Growth

Nandy

Paszuk

Hanke

et al. 2023

ACS Appl. Electron. Mater.

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For vertical-cavity surface-emitting lasers (VCSELs) or photoelectrochemical devices and high efficient III-V/Ge(100) photovoltaics, preparation of double-atomic steps on Ge(100) substrates is highly recommended in order to avoid anti-phase boundaries in the III-V buffer layers. These Ge(100) surfaces were investigated in detail under As- and GaAs-rich MOVPE reactor conditions. During initial growth of III-P buffer layers, however, on an atomically well-ordered Ge(100):As surface, As-P exchange takes place, during which double-layer steps should be preserved. Here, we apply in situ monitoring to study the interaction of P with vicinal Ge(100):As surfaces under realistic, GaAs-rich CVD reactor conditions at growth temperature. In situ optical spectroscopy in combination with surface science techniques in ultra-high vacuum ambience is used to investigate the Ge(100) surface. We show that different Ge(100):As/P heterointerfaces are formed depending on the applied molar flow of phosphorus precursors. Despite the lattice-matched quality of the probing III-P layer, this critical heterointerface impacts significantly the surface roughness and the formation of crystal defects in the subsequently grown III-P buffer layers.

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“…For decades, the researchers were striving their efforts on reducing the threshold current [1][2][3][4][5], improving the output power [6][7][8][9], and expanding the wavelength range [10][11][12][13][14] among other things. They focus their attentions mainly on the behavior of LDs above the threshold region.…”

Section: Introductionmentioning

confidence: 99%

Stimulated emission in GaN-based laser diodes far below the threshold region

et al. 2014

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Estimation of relative defect densities in InGaN laser diodes by induced absorption of photoexcited carriers

Cited by 7 publications

References 21 publications

Reduced Auger Coefficient through Efficient Carrier Capture and Improved Radiative Efficiency from the Broadband Optical Cavity: A Mechanism for Potential Droop Mitigation in InGaN/GaN LEDs

Reduced Auger Coefficient through Efficient Carrier Capture and Improved Radiative Efficiency from the Broadband Optical Cavity: A Mechanism for Potential Droop Mitigation in InGaN/GaN LEDs

Optical In Situ Studies of Ge(100) Interfacial Exchange Reactions in GaAs-Rich MOVPE Reactors for Low-Defect III-P Growth

Stimulated emission in GaN-based laser diodes far below the threshold region

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