Electroreflectance studies of InAs quantum dots with InxGa1−xAs capping layer grown by metalorganic chemical vapor deposition

Chang, Wen-Hao; Chen, Hsiang Yu; Chang, Hsiang-Szu; Chen, W. Y.; Hsu, T. M.; Hsieh, Ting-Yen; Chyi, Jen Inn; Yeh, Nien Tze

doi:10.1063/1.1894613

Cited by 22 publications

(10 citation statements)

References 15 publications

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“…At 5 K, emission is observed below 1.0 µm (1.27 eV) from the hybrid wetting layer -quantum well (WL-QW) that forms in DWELL structures. 13 In Fig. 1(b) we show PL spectra from a selection of 200 nm mesas, obtained with a power density of ∼ 20 W cm −2 .…”

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confidence: 99%

Charged exciton emission at 1.3μm from single InAs quantum dots grown by metalorganic chemical vapor deposition

Cade

Gotoh

Kamada

et al. 2005

Applied Physics Letters

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We have studied the emission properties of self-organized InAs quantum dots (QDs) grown in an InGaAs quantum well by metalorganic chemical vapor deposition. Low-temperature photoluminescence spectroscopy shows emission from single QDs around 1300 nm; we clearly observe the formation of neutral and charged exciton and biexciton states, and we obtain a biexciton binding energy of 3.1 meV. The dots exhibit an s-p shell splitting of approximately 100 meV, indicating strong confinement.Semiconductor self-assembled quantum dots (QDs) are of considerable interest for future telecommunication applications, such as low-threshold lasers and non-classical light sources for quantum key distribution systems. Efficient single-photon emission has recently been demonstrated at visible wavelengths using semiconductor QD structures, 1,2,3 and there have been many detailed investigations into the low-temperature optical characteristics of QDs emitting at 1150 nm or less. 4,5,6 However, to date there have been only a small number of spectroscopic experiments on single QDs emitting in the important telecommunications window around 1300 nm: 7 biexcitonic features have been identified in low-temperature photoluminescence (PL) from QDs grown by molecular beam epitaxy (MBE), 8 whereas similar investigations for QDs fabricated by metalorganic chemical vapor deposition (MOCVD) show an unclear power dependence in the emission. 9Quantum dot structures grown by MOCVD have potentially a large commercial value due to the high growth rates achievable; however, for applications at telecommunication wavelengths the growth is complicated by large strain effects and complex surface dynamics within the dot layers. 10 Therefore, there is a strong motivation for studying the optical characteristics of these structures in relation to other fabrication techniques. Here, we report on the emission properties of single QDs in a novel dotsin-well (DWELL) heterostructure grown by MOCVD. We present low-temperature PL spectra from individual QDs with an emission wavelength of 1300 nm; powerdependent measurements clearly reveal the formation of an exciton-biexciton system, with a biexciton binding energy of more than 3 meV. We also identify recombination from charged exciton and biexciton complexes, and we observe a large energy difference between s-and p-shell states.The QDs were fabricated using conventional lowpressure MOCVD on a (100) GaAs substrate: an InAs(:Bi) dot layer was deposited in a 5 nm In 0.12 Ga 0.88 As(:Bi) quantum well (QW), and the DWELL heterostructure grown between GaAs barrier layers and InGaP cladding layers. Bismuth doping was found to significantly improve the PL intensity and emission wavelength of the dots. The DWELL structure results in a pronounced red-shift relative to similar InAs/GaAs systems due to effects such as strain relaxation 11 and alloy decomposition. 12 Atomic force microscopy (AFM) measurements on similar samples suggest a dot size of < 15 nm with elongation along the [011] axis; the QD sheet density is estimated as 2 ...

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confidence: 99%

Charged exciton emission at 1.3μm from single InAs quantum dots grown by metalorganic chemical vapor deposition

Cade

Gotoh

Kamada

et al. 2005

Applied Physics Letters

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“…When the QDs were capped with a 5-nm-thick In 0.15 Ga 0.85 As overgrown layer, the ground state transition is enhanced and redshifts to 1.038 eV. The low-energy shift could be due to a decreasing strain inside the QD, an increasing effective QD size caused by the strain-driven decomposition of the InGaAs layer, and the lowing of the lateral confinement [7][8][9][10][11]. Fig.…”

Section: Resultsmentioning

confidence: 94%

“…An effective method to achieve the 1.3 m spectral region is to cover an InGaAs thin layer to the InAs/GaAs QDs [5,6]. The InAs/GaAs QDs covered by InGaAs layers can redshift the QD emission by reduction of the residual compressive strain, increment of QD size, strain-driven decomposition of the InGaAs layer, and lowing of the lateral confinement (barrier lowing) [5,[7][8][9][10][11]. Although 1.3-m InAs/GaAs laser can be implemented using this approach, the fundamental properties of the InAs/GaAs QDs covered by InGaAs layers are not well understood.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence studies of InAs/GaAs quantum dots covered by InGaAs layers

Shu¹,

Wang²,

Shen³

et al. 2010

Materials Science and Engineering: B

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“…The conductive band structure of WL+QW used in calculations has been shown in top panel of Fig. 4, the thickness of WL t WL is taken to be 0.33 nm [15]. However, calculations based on nominal indium concentration x ¼ 0:15 fail to match with the experimental results, further calculations emphasize the actual indium concentration in the In 0.15 Ga 0.85 As QW is x ¼ 0:136 instead of nominal value.…”

Section: Article In Pressmentioning

confidence: 98%

“…Although the optical properties of In x Ga 1Àx As/GaAs CVQD were studied by photomodulated reflectance (PR) [12,13], contactless electroreflectance (CER) [14] and electroreflectance (ER) [15,16] spectroscopy, there is still little work conducted with piezomodulated reflectance (PzR) spectroscopy, to our knowledge. In this paper, we use PzR technique to study the optical transitions of an InAs DWELL and an InAs CVQD.…”

Section: Introductionmentioning

confidence: 99%