Excitons localization effects in GaAsN/GaAs epilayers grown by MOCVD

Saidi, F.; Hassen, F.; Maâref, H.; Auvray, Laurent; Dumont, H.; Monteil, Y.

doi:10.1016/s0928-4931(02)00074-7

Cited by 24 publications

(21 citation statements)

References 11 publications

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“…At higher N%, no significant variation in the FWHM with a change in excitation level is observed. Further, the PL spectra at these high N concentrations can be resolved into two closely spaced peaks, separated by ϳ9 meV, similar to those observed by Saidi et al 28 in GaAsN epilayers. The absence of this additional peak in the QWs with low N concentration suggests that this may be related to a modulation of the band structure.…”

Section: Discussionsupporting

confidence: 83%

Nitrogen incorporation and optical studies of GaAsSbN∕GaAs single quantum well heterostructures

Nunna¹,

Iyer²,

Wu³

et al. 2007

Journal of Applied Physics

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In this work, the effects of N incorporation on the optical properties of GaAsSbN / GaAs single quantum wells ͑SQWs͒ have been investigated using temperature, excitation, and magnetic dependencies of photoluminescence ͑PL͒ characteristics. These layers were grown in an elemental solid source molecular beam epitaxy system with a rf plasma N source. The N concentrations in the range of 0.5%-2.5% were investigated in this study. The SQW with N ϳ 0.5% exhibits a behavior similar to that in an intermediate regime where the contributions from the localized states in the band gap are dominant. The temperature and excitation dependencies of the PL characteristics indicate that for the N concentration of 0.9% and above, the alloy behavior is analogous to that of a regular alloy and the changes in optical properties are only marginal. The conduction band effective mass ͑m eff ͒ values computed from the magnetophotoluminescence spectra using a variational formalism and the band anticrossing model are in good agreement and indicate enhanced values of m eff . However, there is no significant variation in m eff values of QWs for N ജ 0.9%. Small redshift of about 30-50 meV for the temperature variations from 10 to 300 K in conjunction with unusually small blueshift observed in the excitation dependence of PL for N ജ 0.9% indicate that this system holds a great promise for laser applications at 1.55 m and beyond.

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Section: Discussionsupporting

confidence: 83%

Nitrogen incorporation and optical studies of GaAsSbN∕GaAs single quantum well heterostructures

Nunna¹,

Iyer²,

Wu³

et al. 2007

Journal of Applied Physics

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“…It exhibits an anomalous behavior, the so-called S-shape. From 10 to 45 K the emission energy decreases as expected, but an increase is seen between 70 K and 90 K. This S-shape behavior is attributed to the recombination of photogenerated carriers trapped by localised states within the GaAsN as previously observed [12,17,20]. The S-shape behavior results from the carrier localisation on the modulated potential structure caused by the nitrogen composition fluctuation [20].…”

Section: Resultssupporting

confidence: 72%

“…This PL band emission shows a red shift with increasing the nitrogen content. This phenomena originates from the bandgap reduction of the GaAsN alloys with the increasing nitrogen composition reported elsewhere [7,8,12,20]. In the QW structures, the red shifts, caused by the bandgap reduction with increasing nitrogen content, dominates the blue shift induced by the confinement effect related to the quantum well width.…”

Section: Resultsmentioning

confidence: 51%

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Optical investigation of GaAs_1−xN_x/GaAs heterostructure properties

Saidi

Hassen

Maaref

et al. 2004

Physica Status Solidi (b)

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We have investigated, by photoluminescence (PL), the optical properties of GaAs 1-x N x /GaAs epilayers and GaAs 1-x N x /GaAs quantum well (QW) structures grown by metal organic vapor phase epitaxy (MOVPE) on (001)-oriented GaAs substrates. Different behaviors have been observed for the bulk epilayer and for the QW structures, respectively: (i) a blue shift of the PL bands in both kinds of structures when increasing the excitation density, (ii) an S-shaped PL peak energy versus temperature dependence has been observed for the GaAsN epilayer but a usual behavior is obtained for the QWs. Based in these experimental results, we have suggested that the carrier recombination mechanisms in the epilayer and in the quantum well structure are different. An enhanced exciton-localization-like mode for the epilayer is observed.

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“…3,11 From previous experiments the dependence of GaN x As 1−x band gap energy and the behavior of the confined ground state energy in GaNAs/GaAs QWs have been studied. Deeper N-induced localized energy states lead to a characteristic S-shaped temperature dependence of PL emission energy of Ga(In)NAs/GaAs QWs, 3,4,10,[12][13][14][15][16][17] however reported dependencies vary widely depending on growth conditions. a Author to whom correspondence should be addressed; electronic mail: ELBORG.Martin@nims.go.jp Due to its extremely large bowing factor, the incorporation of N into GaAs enables the tuning of the band gap from 1.42 -1.0 eV for N concentrations of 0 -5%, 1 which makes the material useful for application in optical detectors, sub-cells in multi-junction solar cells, 18 and long-wavelength emitters.…”

Section: Introductionmentioning

confidence: 99%

Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs

et al. 2016

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We investigate the optical transitions of GaNxAs1−x quantum wells (QWs) embedded in wider band gap AlGaAs. A combination of absorption and emission spectroscopic techniques is employed to systematically investigate the properties of GaNAs QWs with N concentrations ranging from 0 – 3%. From measurement of the photocurrent spectra, we find that besides QW ground state and first excited transition, distinct increases in photocurrent generation are observed. Their origin can be explained by N-induced modifications in the density of states at higher energies above the QW ground state. Photoluminescence experiments reveal that peak position dependence with temperature changes with N concentration. The characteristic S-shaped dependence for low N concentrations of 0.5% changes with increasing N concentration where the low temperature red-shift of the S-shape gradually disappears. This change indicates a gradual transition from impurity picture, where localized N induced energy states are present, to alloying picture, where an impurity-band is formed. In the highest-N sample, photoluminescence emission shows remarkable temperature stability. This phenomenon is explained by the interplay of N-induced energy states and QW confined states.

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Excitons localization effects in GaAsN/GaAs epilayers grown by MOCVD

Cited by 24 publications

References 11 publications

Nitrogen incorporation and optical studies of GaAsSbN∕GaAs single quantum well heterostructures

Nitrogen incorporation and optical studies of GaAsSbN∕GaAs single quantum well heterostructures

Optical investigation of GaAs_1−xN_x/GaAs heterostructure properties

Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs

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Excitons localization effects in GaAsN/GaAs epilayers grown by MOCVD

Cited by 24 publications

References 11 publications

Nitrogen incorporation and optical studies of GaAsSbN∕GaAs single quantum well heterostructures

Nitrogen incorporation and optical studies of GaAsSbN∕GaAs single quantum well heterostructures

Optical investigation of GaAs1−xNx/GaAs heterostructure properties

Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs

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Product

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Optical investigation of GaAs_1−xN_x/GaAs heterostructure properties