Homogeneous and inhomogeneous linewidth broadening of single polar GaN/AlN quantum dots

Demangeot, F.; Simeonov, D.; Butté, R.; Grandjean, N.

doi:10.1002/pssc.200880971

Cited by 15 publications

(11 citation statements)

References 13 publications

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“…Then, the constants Γ 0 , γ A , and Γ LO were fitted to the data with resulting values of 1 ± 0.1 meV, 18 ± 2 µeV/K, and 3.57 ± 0.26 eV, respectively. The extracted value γ A is larger than the one obtained by Demangeot et al [46], suggesting that the coupling strength to phonons is specific to each QD as illustrated by linewidth statistics. In Fig.…”

Section: Resultscontrasting

confidence: 72%

Toward Bright and Pure Single Photon Emitters at 300 K Based on GaN Quantum Dots on Silicon

et al. 2020

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Quantum dots (QDs) based on III-nitride semiconductors are promising for single photon emission at non-cryogenic temperatures due to their large exciton binding energies. Here, we demonstrate GaN QD single photon emitters operating at 300 K with g (2) (0) = 0.17±0.08 under continuous wave excitation. At this temperature, single photon emission rates up to 6 × 10 6 s −1 are reached while g (2) (0) ≤ 0.5 is maintained. Our results are achieved for GaN QDs embedded in a planar AlN layer grown on silicon, representing a promising pathway for future interlinkage with optical waveguides and cavities. These samples allow exploring the limiting factors to key performance metrics for single photon sources, such as brightness and single photon purity. While high brightness is assured by large exciton binding energies, the single photon purity is mainly affected by the spectral overlap with the biexcitonic emission. Thus, the performance of a GaN QD as a single photon emitter depends on the balance between the emission linewidth and the biexciton binding energy. We identify small GaN QDs with an emission energy in excess of 4.2 eV as promising candidates for future room temperature applications, since the biexciton binding energy becomes comparable to the average emission linewidth of around 55 meV.Quantum dots (QDs) based on III-V semiconductors have attracted a lot of attention for their use as nonclassical light sources, with the single photon source being the simplest and most elemental representative. Such a source of single photons should be as bright as possible, while retaining a high single photon purity [1, 2]. However, key metrics for such QD-based single photon sources are usually achieved at cryogenic temperatures with the seminal In(Ga)As/(Al)GaAs system [3][4][5]. Identifying a material platform that can enable sufficiently performant single photon sources up to room temperature remains a challenging quest. In this respect, the main contenders are point defects in wide-bandgap semiconductors (2D materials [6] and bulk semiconductors [7, 8]), nitrogen and silicon vacancies in diamond [9], as well as semiconductor QDs [10][11][12]. It would be advantageous to employ a material system with high integrability into a suitable photonic environment that offers epitaxial control. In this regard, III-nitrides offer a unique possibility as bipolar doping can be achieved, foreign and homoepitaxial substrates are available, and growth and processing techniques are well established, leading to their widespread implementation at an industrial scale for solid state lighting.III-nitrides have shown promising advances in terms of single photon emission (SPE) by employing GaN/AlN [13,14], GaN/AlGaN [15,16] and InGaN/GaN QDs [17][18][19][20][21]. Furthermore, SPE at temperatures as high as 350 K [22] and two-photon emission up to 50 K [23] have been demonstrated. The progress towards room temperature operation is directly linked to the exciton-phonon coupling. With rising temperature the phonon bath becomes * sebastian.tamariz...

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Section: Resultscontrasting

confidence: 72%

Toward Bright and Pure Single Photon Emitters at 300 K Based on GaN Quantum Dots on Silicon

et al. 2020

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“…The obtained values of c p and E A are comparable to what has been reported earlier for shallow InGaN QDs, 21 but c p is here about one order of magnitude smaller than what was recently reported for significantly deeper GaN/AlN QDs. 22 The shallow localization depth for the investigated GaN QDs is consistent with the asymmetric barrier with AlN below the QDs and Al 0.5 Ga 0.5 N above. The barriers constitute a shallow confinement potential in the conduction band in the presence of a built-in electric field.…”

supporting

confidence: 78%

Size dependent biexciton binding energies in GaN quantum dots

Amloy

Karlsson

et al. 2011

Applied Physics Letters

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Single GaN/Al(Ga)N quantum dots (QDs) have been investigated by means of microphotoluminescence. Emission spectra related to excitons and biexcitons have been identified by excitation power dependence and polarization resolved spectroscopy. All investigated dots exhibit a strong degree of linear polarization (∼90%). The biexciton binding energy scales with the dot size. However, both positive and negative binding energies are found for the studied QDs. These results imply that careful size control of III-Nitride QDs would enable the emission of correlated photons with identical frequencies from the cascade recombination of the biexciton, with potential applications in the area of quantum information processing.

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“…These linewidths are several times higher than many other reported values for InGaN QDs. 28,30,31 We have attributed the larger-than-expected ZP-linewidth to the likely significant presence of spectral diffusion in the sample, given the probable high density of point defects associated with the Si dopants, which act as charge trapping sites in the regions in which QDs are formed, as discussed previously. It would seem consistent that we observe a correspondingly larger acoustic phonon coupling constant, as the magnitude of the spectral diffusion is also expected to increase with temperature.…”

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confidence: 72%

“…The variation of linewidth with increasing temperature gives us insight into the influence of phonons on these m-plane QDs. We expect significant acoustic-phonon broadening in the nitrides, 28 whilst having minimal coupling to optical phonons at the range of temperatures measured due to the large optical phonon energy in GaN (92meV). 29 The linewidth Γ of QDs fit well with the standard equation for bulk or QW semiconductors, 30 Γ(𝑇) = Γ 0 + 𝛾 a 𝑇 + 𝛾 b exp(−𝐸 a /𝑘 B 𝑇) with terms representing the zero-phonon linewidth (ZP-linewidth), acoustic phonon coupling and delocalization of carriers from the QD respectively.…”

mentioning

confidence: 84%

Ultrafast, Polarized, Single-Photon Emission from m-Plane InGaN Quantum Dots on GaN Nanowires

et al. 2016

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We demonstrate single-photon emission from self-assembled m-plane InGaN quantum dots (QDs) embedded on the side-walls of GaN nanowires. A combination of electron microscopy, cathodoluminescence, time-resolved microphotoluminescence (μPL), and photon autocorrelation experiments give a thorough evaluation of the QD structural and optical properties. The QD exhibits antibunched emission up to 100 K, with a measured autocorrelation function of g(0) = 0.28(0.03) at 5 K. Studies on a statistically significant number of QDs show that these m-plane QDs exhibit very fast radiative lifetimes (260 ± 55 ps) suggesting smaller internal fields than any of the previously reported c-plane and a-plane QDs. Moreover, the observed single photons are almost completely linearly polarized aligned perpendicular to the crystallographic c-axis with a degree of linear polarization of 0.84 ± 0.12. Such InGaN QDs incorporated in a nanowire system meet many of the requirements for implementation into quantum information systems and could potentially open the door to wholly new device concepts.

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Homogeneous and inhomogeneous linewidth broadening of single polar GaN/AlN quantum dots

Cited by 15 publications

References 13 publications

Toward Bright and Pure Single Photon Emitters at 300 K Based on GaN Quantum Dots on Silicon

Toward Bright and Pure Single Photon Emitters at 300 K Based on GaN Quantum Dots on Silicon

Size dependent biexciton binding energies in GaN quantum dots

Ultrafast, Polarized, Single-Photon Emission from m-Plane InGaN Quantum Dots on GaN Nanowires

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