Role of Arsenic During Aluminum Droplet Etching of Nanoholes in AlGaAs

Heyn, Ch.; Zocher, Michel; Schnüll, S.; Hansen, W.

doi:10.1186/s11671-016-1648-6

Cited by 9 publications

(6 citation statements)

References 25 publications

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“…The surface also shows signs of droplet running [33]. The results are a clear indication that the Al/As-ratio used resulted in a bimodal hole distribution [31,32]. This matches well with the quantification of the effective etch material, which finds at least three times more etch material was used than intended.…”

Section: Evaluation Of the Growth Parameterssupporting

confidence: 77%

“…Better symmetry leads to a lower and thus preferred FSS, and the growth of uniform QDs with a slightly lower density would be beneficial to reduce the charge noise from QDs nearby. This can be achieved by (a combination of) etching under higher As-flux conditions [32], by using lower temperature [38] or less etch material [23]. These optimizations nevertheless should be conducted carefully while keeping the impurity levels in the matrix material low, as some of the practical solutions might be a tradeoff that will increase impurities (e.g., lower temperature).…”

Section: Discussionmentioning

confidence: 99%

“…The use of 1.3 ML eq Al, as with the photonic sample, results in an effective amount of etching material, of at least 0.9 ML eq , which is at least a factor of 3 higher than intended. If the etch amount exceeds a certain threshold, which is dependent on the As-BEP and the growth temperature, a second nucleation phase of the metal droplets occurs, which leads to a bimodal size distribution [31,32]. A bimodal QD distribution could explain the findings of two groups of QDs [1]: One group of QDs has narrow linewidths, while the other has broad linewidths.…”

Section: Evaluation Of the Growth Parametersmentioning

confidence: 99%

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Charge Tunable GaAs Quantum Dots in a Photonic n-i-p Diode

et al. 2021

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In this submission, we discuss the growth of charge-controllable GaAs quantum dots embedded in an n-i-p diode structure, from the perspective of a molecular beam epitaxy grower. The QDs show no blinking and narrow linewidths. We show that the parameters used led to a bimodal growth mode of QDs resulting from low arsenic surface coverage. We identify one of the modes as that showing good properties found in previous work. As the morphology of the fabricated QDs does not hint at outstanding properties, we attribute the good performance of this sample to the low impurity levels in the matrix material and the ability of n- and p-doped contact regions to stabilize the charge state. We present the challenges met in characterizing the sample with ensemble photoluminescence spectroscopy caused by the photonic structure used. We show two straightforward methods to overcome this hurdle and gain insight into QD emission properties.

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Section: Evaluation Of the Growth Parameterssupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Evaluation Of the Growth Parametersmentioning

confidence: 99%

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Charge Tunable GaAs Quantum Dots in a Photonic n-i-p Diode

et al. 2021

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“…Finally, the droplet material is removed by spreading over the substrate surface, and nanoholes are formed. More details of the LDE process and mechanism have been discussed in previous articles (e.g., [ 27 , 33 , 34 , 35 ]). For QD generation, the LDE nanoholes are filled by deposition of a GaAs amount corresponding to film thickness of 0.3 to

nm of GaAs.…”

Section: Methodsmentioning

confidence: 99%

Luminescence from Droplet-Etched GaAs Quantum Dots at and Close to Room Temperature

et al. 2021

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Epitaxially grown quantum dots (QDs) are established as quantum emitters for quantum information technology, but their operation under ambient conditions remains a challenge. Therefore, we study photoluminescence (PL) emission at and close to room temperature from self-assembled strain-free GaAs quantum dots (QDs) in refilled AlGaAs nanoholes on (001)GaAs substrate. Two major obstacles for room temperature operation are observed. The first is a strong radiative background from the GaAs substrate and the second a significant loss of intensity by more than four orders of magnitude between liquid helium and room temperature. We discuss results obtained on three different sample designs and two excitation wavelengths. The PL measurements are performed at room temperature and at T = 200 K, which is obtained using an inexpensive thermoelectric cooler. An optimized sample with an AlGaAs barrier layer thicker than the penetration depth of the exciting green laser light (532 nm) demonstrates clear QD peaks already at room temperature. Samples with thin AlGaAs layers show room temperature emission from the QDs when a blue laser (405 nm) with a reduced optical penetration depth is used for excitation. A model and a fit to the experimental behavior identify dissociation of excitons in the barrier below T = 100 K and thermal escape of excitons from QDs above T = 160 K as the central processes causing PL-intensity loss.

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“…In the characterization of aluminum droplets in Fig. 2a, nano pits are etched when the As beam is turned off, which may be caused by the high As background (Heyn et al 2016). In Fig.…”

Section: Surface Morphology Of Nanoporous Before and After Annealingmentioning

confidence: 99%

Study on the asymmetry of nanopore in Al droplet etching

Shen

Liu

et al. 2021

Opt Quant Electron

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In the local droplet etching (LDE) method, the fine split structure (FSS) of quantum dots (QDs) is directly related to the shape of the nanopores formed after annealing. The formation of highly symmetrical nanoporous is the key to the preparation of GaAs/AlGaAs QDs with small FSS. The measurement and characterization of the nano pore shape before and after annealing showed that the density of the nano pore contours is different in different directions, indicating that the slope of the sidewall of the nano pore is different. Therefore, the QDs formed by LDE still have FSS. It has also been observed in experiments that one of the reasons for the asymmetry of the nanoporous is that the etching points covered by the Al droplets on the AlGaAs surface are not in the center of the droplets, which is caused by the supersaturation and maturation of Al atoms during the formation of the droplets. The asymmetry of the annular wall of the nano pore will cause the increase of the FSS of the QDs in the shallow nano pore. When the nano pore is deep enough, the influence of the annular wall of the nano pore on the QDs can be completely ignored, which greatly simplifies the preparation of nano pore. It has certain guiding significance of the preparation of nanoporous required for the growth of QDs with small FSS.

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Role of Arsenic During Aluminum Droplet Etching of Nanoholes in AlGaAs

Cited by 9 publications

References 25 publications

Charge Tunable GaAs Quantum Dots in a Photonic n-i-p Diode

Charge Tunable GaAs Quantum Dots in a Photonic n-i-p Diode

Luminescence from Droplet-Etched GaAs Quantum Dots at and Close to Room Temperature

Study on the asymmetry of nanopore in Al droplet etching

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