Extended, monolayer flat islands and exciton dynamics in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ga</mml:mi></mml:mrow><mml:mrow><mml:mn>0.47</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">In</mml:mi></mml:mrow><mml:mrow><mml:mn>0.53</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:

Liu, X.; Nilsson, S.; Samuelson, Lars; Seifert, Werner; Souza, P. L.

doi:10.1103/physrevb.47.2203

Cited by 20 publications

(5 citation statements)

References 8 publications

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“…No PL splitting, meaning two peaks emitted by extended flat areas of different thicknesses on the same QW layer, was observed. This PL splitting has been previously reported for ultrathin QWs grown lattice matched to the substrate (GaAs/AlGaAs [16], InGaAs/InP [17]). More recently, possible mechanisms for the nucleation of InAs QDs on GaAs by MOVPE have been thoroughly described [18] and improvements in the QDs size distribution and morphology by playing with different growth parameters have been reported [19][20][21][22][23].…”

Section: Introductionsupporting

confidence: 83%

“…2D InAs extended monolayer terraces are formed which have an area larger than the Bohr radius (around 40 angstroms), as it should be when a single narrow PL peak is observed. Such extended monolayer flat areas have already been reported for the GaAs/AlGaAs system [16] and for InGaAs layers lattice matched to InP [17]. It should be noted that the layers probed by PL are buried.…”

Section: Morphological Aspectssupporting

confidence: 66%

“…The striking feature of these PL spectra is that they show PL peaks (FWHM between 6 and 18 meV) at four specific energies, namely: 1.494 eV, 1.475 eV, 1.450 eV and 1.410 eV, which correspond to the 2D InAs strained layers of different thicknesses. The FWHMs indicate that the buried interfaces have excellent quality [32] and that free exciton emissions are observed [17]. The calculations assume a 70 % band offset for the conduction band, 30 % for the valence band and an energy gap for the strained InAs equal to 0.784 eV [33].…”

Section: Morphological Aspectsmentioning

confidence: 95%

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Early nucleation stages of low density InAs quantum dots nucleation on GaAs by MOVPE

Torelly

Jakomin

Pinto

et al. 2016

Journal of Crystal Growth

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An investigation of ultra-thin InAs layers deposited on GaAs is carried out combining theoretical calculations with results of high-resolution transmission electron microscopy, atomic force microscopy and photoluminescence. Five period InAs/GaAs epilayers were grown by metalorganic vapor phase epitaxy at a very low growth rate, with different InAs deposition times, in order to investigate the morphological and optical evolution from extended 2D InAs flat areas of various thicknesses, starting at 1 monolayer, to the nucleation of 3D InAs islands.The coexistence of extended monolayer-flat 2D terraces of different thicknesses and 3D islands is demonstrated. Optically active InAs 2D terraces with a thickness beyond the critical value are detected. For longer deposition times, quantum dots are nucleated and their size increases at the expense of the 3 monolayer thick 2D layers.

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Section: Introductionsupporting

confidence: 83%

Section: Morphological Aspectssupporting

confidence: 66%

Section: Morphological Aspectsmentioning

confidence: 95%

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Early nucleation stages of low density InAs quantum dots nucleation on GaAs by MOVPE

Torelly

Jakomin

Pinto

et al. 2016

Journal of Crystal Growth

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“…6,9 However, results obtained by direct methods such as TEM and STM on the one side and luminescence methods such as PL and CL on the other side are often controversial concerning the real interface structure and the interpretation of the experimental data from QWs. 1,10 The reason is probably twofold: ͑i͒ the PL line shape is determined by lateral exciton transfer between discrete, large interface islands 11 and by exciton localization due to confinement potential fluctuations; 12 ͑ii͒ the probing area of the exciton is larger than the respective component of the roughness, which occurs on a nm scale, leading to an averaging process in luminescence experiments and hence to characteristic line shapes. 13 Recently, Brunner et al 14 and Hess et al 15 demonstrated by micro-PL and optical near field PL, respectively, that at least for low temperatures and thin QWs the line shape of PL spectra is determined by the envelope of many very narrow lines due to excitons localized at lateral potential fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Exciton localization, photoluminescence spectra, and interface roughness in thin quantum wells

et al. 1996

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The combination of conventional photoluminescence ͑PL͒, PL-excitation ͑PLE͒, and micro-PL spectroscopies is used to study the influence of interface roughness on luminescence properties of thin GaAs/Al 0.3 Ga 0.7 As single quantum wells ͑QWs͒. The QWs were prepared under different growth conditions, resulting in different interface roughness. We discuss the splitting of PL spectra into two ͑or more͒ main lines, the pronounced fine structure of the micro-PL spectra and the low-energy shift of the PL lines with respect to the PLE spectrum in terms of a phenomenological interface model. For low temperatures exciton localization due to interface fluctuations with different length scales determines most of the luminescence features. One consequence is a strong suppression of the PLE signal on the low-energy side of the spectra. Therefore in this case the PLE spectrum cannot be used as a measure for the absorption strength or as an indicator for impurity bound excitons. ͓S0163-1829͑96͒03828-3͔

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“…A existência de um espectro com duas emissões em energias distintas, como no caso da amostra 7.2-630, indica que durante o crescimento foram formadas ilhas com espessuras que diferem em uma monocamada [44] ou estas emissões são provenientes de diferentes camadas depositadas que apresentaram uma diferente espessura da camada de molhamento.…”

Section: Fotoluminescênciaunclassified

Transição No Modo De Crescimento 2d Para 3d De Inas Sobre Gaas Analisada Por Fotoluminescência

Torelly¹

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AgradecimentosAos meus pais e minha tia, Maria José, Ricardo e Elisa, por todo o suporte que sempre me deram.Aos meus orientadores, Patricia Lustoza de Souza e Mauricio Pamplona Pires, por me guiarem durante a minha vida acadêmica, sempre incentivando o desenvolvimento da melhor maneira possível.À minha família que sempre me apoiou e mostrou que a perseverança, o trabalho e a união podem superar qualquer obstáculo. À Sara, minha querida, por estar sempre ao meu lado.Aos amigos Daniel Micha, Germano Penello e Rudy Kawabata, por todos os ensinamentos, trabalhos, discussões e momentos de diversão que compartilhamos dentro e fora do laboratório.Ao pessoal do LabSem que se esforça ao máximo para uma pesquisa cada vez melhor: Elaine Nunes, Renato Mourão, Daniela Szwarcman, Roberto Jakomin, Loïk Gence, Luciana Dornelas, Lesslie Guerra, Eleonora Weiner, Janeth Collazos, Eric Hermanny, José Ruiz, Amanda Hermann, Paulina, Marcelo Lessa.Aos membros do DISSE, por todo o trabalho desenvolvido durante os anos de funcionamento do INCT, em especial a Marcos Degani e Marcelo Maialle pela ajuda nas simulações.Aos pesquisadores Fernando Ponce, Rodrigo Prioli, Hongen Xie e Paula Caldas, das universidades PUC e Arizona State University, pela sua contribuição na caracterização, discussão dos resultados e publicação da pesquisa obtida com as amostras apresentadas neste trabalho.À PUC, por abrir os caminhos da educação e do trabalho a mim e a tantos outros pesquisadores, professores e alunos.Às agências de fomento, CNPq, CAPES e FAPERJ, sem as quais este trabalho não seria possível. O objetivo é estudar a transição entre os modos bidimensional e tridimensional no crescimento epitaxial em reator MOVPE, com a formação de pontos quânticos autoorganizados pelo método Stranski-Krastanov e a subsequente aplicação da técnica de indium flush. São analisados espectros de fotoluminescência, simulações dos níveis de energia, imagens de microscopia de força atômica e microscopia eletrônica de transmissão para a obtenção de informações sobre densidade, tamanho, uniformidade e energia das transições radiativas dos pontos quânticos. Imagens de microscopia eletrônica de transmissão revelam a qualidade das interfaces e a espessura das camadas. Palavras-chavePoço quântico; ponto quântico; semicondutores; luminescência; células solares. Transmission electron microscopy images reveal the interfaces quality and layers thicknesses.

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Extended, monolayer flat islands and exciton dynamics inGa0.47In0.53

Cited by 20 publications

References 8 publications

Early nucleation stages of low density InAs quantum dots nucleation on GaAs by MOVPE

Early nucleation stages of low density InAs quantum dots nucleation on GaAs by MOVPE

Exciton localization, photoluminescence spectra, and interface roughness in thin quantum wells

Transição No Modo De Crescimento 2d Para 3d De Inas Sobre Gaas Analisada Por Fotoluminescência

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