Optical properties of GaN quantum dots grown on nonpolar (11-20) SiC by molecular-beam epitaxy

Founta, S.; Rol, Fabian; Bellet‐Amalric, E.; Bleuse, J.; Daudin, B.; Gayral, B.; Mariette, H.; Moisson, C.

doi:10.1063/1.1905807

Cited by 64 publications

(58 citation statements)

References 18 publications

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“…Nevertheless, experimental results indicate increased recombination rates in nonpolar nitride QDs in comparison to polar QDs. 3 Recent theoretical studies have investigated the influence of intrinsic fields on the single-particle states concerning the sign of piezoelectric constants, 4 geometry, 5 and concentration. 6 These studies revealed only a marginal spatial overlap of the electron and hole single-particle ground state in nonpolar QDs implying a very slow recombination due to dipole transitions between the ground states.…”

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confidence: 99%

Strong dipole coupling in nonpolar nitride quantum dots due to Coulomb effects

Schuh

Barthel

Marquardt

et al. 2012

Applied Physics Letters

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Optical properties of polar and nonpolar nitride quantum dots (QDs) are determined on the basis of a microscopic theory which combines a continuum elasticity approach to the polarization potential, a tight-binding model for the electronic energies and wavefunctions, and a many-body theory for the optical properties. For nonpolar nitride quantum dots, we find that optical absorption and emission spectra exhibit a weak ground-state oscillator strength in a single-particle calculation whereas the Coulomb configuration interaction strongly enhances the ground-state transitions. This finding sheds new light on existing discrepancies between previous theoretical and experimental results for these systems, as a weak ground state transition was predicted because of the spatial separation of the corresponding electron and hole state due to intrinsic fields whereas experimentally fast optical transitions have been observed.

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confidence: 99%

Strong dipole coupling in nonpolar nitride quantum dots due to Coulomb effects

Schuh

Barthel

Marquardt

et al. 2012

Applied Physics Letters

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“…Confining the carriers in dislocation-free quantum dots (QDs) or nanowires (NWs) is a possible approach to overcome the impact of structural defects on the radiative recombination yield. The first growth of a-plane GaN/AlN QD structure was demonstrated by the Grenoble research group in 2005 [49]. The emission-energy behavior in these structures as compared to that of the (0001) GaN QDs was a clear fingerprint for a reduced internal electric field present in the nonpolar nanostructures.…”

Section: The First Nonpolar Low-dimensional Nitridebased Structuresmentioning

confidence: 96%

Development and prospects of nitride materials and devices with nonpolar surfaces

Paskova

2008

Physica Status Solidi (b)

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IntroductionThe commercial fabrication of lightemitting diodes (LED) and laser diodes (LD) from the ultraviolet to the amber, as well as the development of highpower high electron mobility transistors (HEMT) suitable for numerous telecom applications have been driven by the tremendous improvement in the nitride materials quality. Despite remarkable achievements during the last decade, however, the device performance is hampered by the presence of strong spontaneous and piezoelectric polarization fields along the typical [0001] growth direction in the wurtzite nitride materials [1]. As a consequence of these strong internal fields, the quantum wells (QW), typically used in the active region of optical emitter devices, have a triangular potential profile and the oscillator strength for optical transitions is reduced by several orders of magnitude, depending on the QW thickness [2,3]. A similar deterioration effect is observed in the nitride-based HEMT devices due to a polarization-generated charge. A typical AlGaN/GaN HEMT built in the [0001] growth direction experiences a channel charge of more than 1 × 10 13 cm

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“…A detailed description of the growth process can be found in Refs. [7,8]. Atomic force microscopy performed on the upper uncapped dot layer of similar samples revealed a density of dots of 1.2 × 10 11 cm -2 for sample A and 0.6 × 10 11 cm -2 for sample B.…”

Section: Samples and Experimentsmentioning

confidence: 98%

Influence of strain in the reduction of the internal electric field in GaN/AlN quantum dots grown on a‐plane 6H‐SiC

Cros

Budagosky

García‐Cristóbal

et al. 2006

Physica Status Solidi (b)

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The strain state of stacks of GaN/AlN quantum dots (QDs) grown on (0001) and (1120) 6H-SiC has been investigated by means of Raman spectroscopy. Depending on the orientation of the wurtzite axis with respect to the growth direction it is found that the piezoelectric contribution to the electrostatic potential may either reinforce that arising from the spontaneous polarization or oppose it. The experimental results are compared with a theoretical model for the strain and polarization field in QDs of both orientations that allows the calculation of the electrostatic potential in the QDs. Both the experimental results and the theoretical model indicate that the internal electric field and electrostatic potential are strongly reduced in the QDs grown on (1120) 6H-SiC as compared to those grown along the wurtzite c-axis.

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Optical properties of GaN quantum dots grown on nonpolar (11-20) SiC by molecular-beam epitaxy

Cited by 64 publications

References 18 publications

Strong dipole coupling in nonpolar nitride quantum dots due to Coulomb effects

Strong dipole coupling in nonpolar nitride quantum dots due to Coulomb effects

Development and prospects of nitride materials and devices with nonpolar surfaces

Influence of strain in the reduction of the internal electric field in GaN/AlN quantum dots grown on a‐plane 6H‐SiC

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