Cubic GaN∕AlN multiple quantum well photodetector

DeCuir, E. A.; Manasreh, M. O.; Tschumak, E.; Schörmann, Jörg; As, D. J.; Lischka, K.

doi:10.1063/1.2936279

Cited by 24 publications

(11 citation statements)

References 24 publications

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“…The GaN/AlN conduction band offset in Γ valley (minimum) was taken as ΔE c = 1.6eV [5,7]. We used pure GaN as the well material and Al x Ga 1-x N as the barrier and embedded layer material.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…Besides their application in devices operating on the basis of interband transitions (laser and light emitting diodes in blue-green and ultraviolet spectral range [1][2][3]), electronic and optical properties of GaN and related materials make them particularly suitable for intersubband (ISB) based devices. Due to large values of the conduction band discontinuity and very short ISB absorption recovery times measured in femtoseconds, GaN/Al(Ga)N planar nanostructures are becoming the foremost system for ISB devices operating at telecommunication wavelengths, such as fast multiple quantum well (QW) photodetectors or modulators [4][5][6][7][8]. On the other hand, by changing the QW thickness and Al molar fraction in AlGaN alloy it is possible to tune the ISB absorption peak wavelength to mid-infrared (mid-IR) or terahertz (THz) spectral range, as well [5,[9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors

et al. 2014

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Article:Radosavljevic, A, Radovanovic, J, Milanovic, V et al.(1 more author) (2015) Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors. Optical and Quantum Electronics, 47 (4). [865][866][867][868][869][870][871][872] https://doi.org/10.1007/s11082-014-0016-y eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Abstract We propose a method which delivers optimal cubic GaN/AlGaN quantum well (QW) profiles such that both the Stark effect and peak intersubband absorption from the ground to the first excited electronic state, in a prescribed range of bias electric fields, are maximized. Our method relies on the Genetic Algorithm which finds globally optimal structures with a predefined number of embedded layers. We investigate simple rectangular quantum wells with embedded step layers for applications in tunable mid-infrared photodetectors. The effects of band nonparabolicity are taken into account to refine our model. Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors

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Section: Numerical Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors

et al. 2014

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“…Among them, traditional c-plane AlGaN/GaN multiple quantum wells (MQWs) structures are widely used. However, the polarization induced internal electric field reduces not only the ISB transition probability but also the photocurrent transportation, which significantly reduces the devices' performance.Some groups eliminated the influence of internal electric field by non-polar GaN based quantum structures [1] and cubic ones [2] . To overcome the poor growth quality of samples in these methods, we use step quantum wells (SQWs) structure in which the internal electric field is proved almost completely eliminated.…”

mentioning

confidence: 99%

“…Some groups eliminated the influence of internal electric field by non-polar GaN based quantum structures [1] and cubic ones [2] . To overcome the poor growth quality of samples in these methods, we use step quantum wells (SQWs) structure in which the internal electric field is proved almost completely eliminated.…”

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confidence: 99%

Intersubband Transition in AlGaN/GaN step quantum wells at 3–5 μm

Rong

Wang

Chen

et al. 2014

Asia Communications and Photonics Conference 2014

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We demonstrate intersubband absorptions and photocurrent response at wavelength of 3-5μm in nitride-based semiconductor step quantum wells. The structures consist of a 1.8nm thick Al 0.5 Ga 0.5 N barrier, a 1.8nm thick GaN well and a 16nm thick Al 0.25 Ga 0.75 N step barrier. With this approach, one can create a virtually flat band potential energy profile in the step barrier layers, which is confirmed by analysing the temperature dependence dark current results.GaN based intersubband (ISB) devices has attracted much research attention due to the benefits of large conduction band offset, ultra-fast electron relaxation time, and UV-region capability. Among them, traditional c-plane AlGaN/GaN multiple quantum wells (MQWs) structures are widely used. However, the polarization induced internal electric field reduces not only the ISB transition probability but also the photocurrent transportation, which significantly reduces the devices' performance.Some groups eliminated the influence of internal electric field by non-polar GaN based quantum structures [1] and cubic ones [2] . To overcome the poor growth quality of samples in these methods, we use step quantum wells (SQWs) structure in which the internal electric field is proved almost completely eliminated. By this structure, we realized the detection with photoabsorption and photocurrent at wavelength of 3-5μm.We designed and grew Al 0.5 Ga 0.5 N/GaN/Al 0.25 Ga 0.75 N SQWs on c-plane sapphire substrate. The structure was designed based on solving self-consistent Schrödinger-Poisson equations. It shows that when we use a structure of Al 0.5 Ga 0.5 N/GaN/Al 0.25 Ga 0.75 N (1.8nm/1.8nm/16nm, barrier/well/step barrier) SQWs, the internal electric field of step barrier layer can be completely erased. The conduction band structure and energy levels of the designed structure are shown in Fig.1. There are several separated energy levels: the ground state (e 1 ) and the quasi-continuum states (e 2 -e 11 ). High resolution TEM (Fig.2) of the grown sample shows that each layer thickness is 7ML/6ML/65ML, respectively. By simulation of XRD diffraction peaks, we estimated the Al component of each layer, which is in accord with the designed structures.Afterwards the temperature dependence dark current is measured. It shows the symmetric IV characteristic dark current at high temperature (>100K) and the asymmetric one at low temperature. At high temperature, the ground state carriers jump up to quasi-continuum states by thermionic emission. The elimination of internal electric field at wide barrier layer results in the symmetric IV characteristic dark current if we ignore the influence of narrow barrier for it is narrow enough for tunneling. At low temperature, the ground state carriers are confined at the quantum wells.They are very hard to tunnel to the adjacent well at low bias because of the wide step barrier blocking, while they can tunnel at high bias. The asymmetric structure results in the asymmetric tunneling method, and then the asymmetric IV characteristic dark current....

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“…For optoelectronic applications, it is, therefore, desirable to reduce the internal electric field. This can be achieved by using III-nitride materials synthesized in the cubic phase [13][14][15][16] or by changing the growth direction to set the polarization vector at 90 . 17 The later strategy has been implemented using nonpolar growth planes, namely, the m-plane f10 10g 18 or the a-plane f11 20g.…”

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Systematic study of near-infrared intersubband absorption of polar and semipolar GaN/AlN quantum wells

Machhadani

Beeler

Sakr

et al. 2013

Journal of Applied Physics

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We report on the observation of intersubband absorption in GaN/AlN quantum well superlattices grown on ð11 22Þ-oriented GaN. The absorption is tuned in the 1:5-4:5 lm wavelength range by adjusting the well thickness. The semipolar samples are compared with polar samples with identical well thickness grown during the same run. The intersubband absorption of semipolar samples shows a significant red shift with respect to the polar ones due to the reduction of the internal electric field in the quantum wells. The experimental results are compared with simulations and confirm the reduction of the polarization discontinuity along the growth axis in the semipolar case. The absorption spectral shape depends on the sample growth direction: for polar quantum wells the intersubband spectrum is a sum of Lorentzian resonances, whereas a Gaussian shape is observed in the semipolar case. This dissimilarity is explained by different carrier localization in these two cases. V C 2013 AIP Publishing LLC [http://dx

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Cubic GaN∕AlN multiple quantum well photodetector

Cited by 24 publications

References 24 publications

Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors

Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors

Intersubband Transition in AlGaN/GaN step quantum wells at 3–5 μm

Systematic study of near-infrared intersubband absorption of polar and semipolar GaN/AlN quantum wells

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