InGaN/GaN quantum wells with low growth temperature GaN cap layers

Pendlebury, Sarah T.; Parbrook, P. J.; Mowbray, D. J.; Wood, David; Lee, K.B.

doi:10.1016/j.jcrysgro.2007.07.018

Cited by 26 publications

(18 citation statements)

References 14 publications

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“…Thus we introduced a GaN cover layer at the same growth temperature as that of the QW. Similar growth strategies have been reported already in the past ( [7,8,9]) After the growth of the cover layer we have increased the temperature to 800°C (samples B and D) and 850°C (samples C and E), respectively. A typical example with improved structural properties is also shown in Fig.…”

Section: Ramping In the Barrierssupporting

confidence: 70%

Mechanism of thermal degradation in GaInN/GaN quantum wells

Bremers

Jönen

Hoffmann

et al. 2009

Phys. Status Solidi (c)

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In this contribution we focus on degradation processes of GaInN multiple quantum wells (MQWs) used in laser structures grown by metallorganic vapor pressure epitaxy (MOVPE). The influence of ramp‐up time as well as the maximum temperature during growth of the barrier on the quantum well (QW) is investigated. Comparison of X‐ray and photoluminescence (PL) measurements implies that a sufficient thickness of a cover layer grown at low temperature is required to prevent degradation of the QW. In a next step samples were grown using an optimal thermal budget during growth of the active region to investigate the influence of capping layers. To improve crystalline quality of these layers high temperatures are required. Our measurements show that these high temperatures lead to a decrease in average indium concentration of the QWs. This decrease is temperature as well as time dependent (∝ √t) and can only explained by diffusion processes. The activation energies are in the range 0.7‐0.9 eV (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Ramping In the Barrierssupporting

confidence: 70%

Mechanism of thermal degradation in GaInN/GaN quantum wells

Bremers

Jönen

Hoffmann

et al. 2009

Phys. Status Solidi (c)

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“…A reactor pressure of 100 Torr at 1050 • C was applied. Subsequently five (In,Ga)N QWs were grown with a quasi-2T method, discussed in detail elsewhere [40]. For the QW growth a reactor pressure of 300 Torr was applied.…”

Section: Sample Growth Detailsmentioning

confidence: 99%

Structural, electronic, and optical properties ofm-plane InGaN/GaN quantum wells: Insights from experiment and atomistic theory

Schulz¹,

Tanner

O’Reilly

et al. 2015

Phys. Rev. B

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In this paper we present a detailed analysis of the structural, electronic, and optical properties of an m-plane (In,Ga)N/GaN quantum well structure grown by metal organic vapor phase epitaxy. The sample has been structurally characterized by x-ray diffraction, scanning transmission electron microscopy, and 3D atom probe tomography. The optical properties of the sample have been studied by photoluminescence (PL), time-resolved PL spectroscopy, and polarized PL excitation spectroscopy. The PL spectrum consisted of a very broad PL line with a high degree of optical linear polarization. To understand the optical properties we have performed atomistic tight-binding calculations, and based on our initial atom probe tomography data, the model includes the effects of strain and built-in field variations arising from random alloy fluctuations. Furthermore, we included Coulomb effects in the calculations. Our microscopic theoretical description reveals strong hole wave function localization effects due to random alloy fluctuations, resulting in strong variations in ground state energies and consequently the corresponding transition energies. This is consistent with the experimentally observed broad PL peak. Furthermore, when including Coulomb contributions in the calculations we find strong exciton localization effects which explain the form of the PL decay transients. Additionally, the theoretical results confirm the experimentally observed high degree of optical linear polarization. Overall, the theoretical data are in very good agreement with the experimental findings, highlighting the strong impact of the microscopic alloy structure on the optoelectronic properties of these systems.

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“…The LT-GaN barriers prevent the In desorption and relax some strain by crystal lattice deformation, but the quality of the InGaN/ GaN MQWs is not high due to the LT growth of GaN barriers, which will hinder further improvement of device performances. Some groups have used the two step barriers growth to improve the performance of LED [4][5][6][7]. Previously thin LT-GaN layers have been grown before HT-GaN barrier to protect the InGaN well and enhance the quantum efficiency [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…Some groups have used the two step barriers growth to improve the performance of LED [4][5][6][7]. Previously thin LT-GaN layers have been grown before HT-GaN barrier to protect the InGaN well and enhance the quantum efficiency [4,5]. Shim et al [6] reported that MQWs with various potential energy profiles could be intentionally fabricated by gradating the In composition during the well layer growth.…”

Section: Introductionmentioning

confidence: 99%