Photoluminescence killer center in AlGaAs grown by molecular-beam epitaxy

Akimoto, Katsuhiro; Kamada, M.; Taira, K.; Arai, M.; Watanabe, N.

doi:10.1063/1.336938

Cited by 83 publications

(23 citation statements)

References 21 publications

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“…Aluminum alloying in both MOCVD and MBE Al x Ga 1Ϫx As is known to bring residual oxygen impurities into the host material in high concentrations. 13,14 Oxygen codoping is known to enhance the Er 3ϩ emission in GaAs and Al x Ga 1Ϫx As. 8,15 It should be reiterated that the GaAs:Er sample used in this work also contains oxygen, but the amount of oxygen will obviously remain constant in the pressure experiments.…”

Section: B Effects On the Low Temperature Intensitymentioning

confidence: 99%

Photoluminescence studies of erbium-doped GaAs under hydrostatic pressure

Culp

Hömmerich

Redwing

et al. 1997

Journal of Applied Physics

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The photoluminescence properties of metal-organic chemical vapor deposition GaAs:Er were investigated as a function of temperature and applied hydrostatic pressure. The 4 I 13/2 → 4 I 15/2 Er 3ϩ emission energy was largely independent of pressures up to 56 kbar and temperatures between 12 and 300 K. Furthermore, no significant change in the low temperature emission intensity was observed at pressures up to and beyond the ⌫-X crossover at ϳ41 kbar. In contrast, Al x Ga 1Ϫx As:Er alloying studies have shown a strong increase in intensity near the ⌫-X crossover at xϳ0.4. These results suggest that the enhancement is most likely due to a chemical effect related to the presence of Al, such as residual oxygen incorporation, rather than a band structure effect related to the indirect band gap or larger band gap energy. Modeling the temperature dependence of the 1.54 m Er 3ϩ emission intensity and lifetime at ambient pressure suggested two dominant quenching mechanisms. At temperatures below approximately 150 K, thermal quenching is dominated by a ϳ13 meV activation energy process which prevents Er 3ϩ excitation, reducing the intensity, but does not affect the Er 3ϩ ion once it is excited, leaving the lifetime unchanged. At higher temperatures, thermal quenching is governed by a ϳ115 meV activation energy process which deactivates the excited Er 3ϩ ion, quenching both the intensity and lifetime. At 42 kbar, the low activation energy process was largely unaffected, whereas the higher activation energy process was significantly reduced. These processes are proposed to be thermal dissociation of the Er-bound exciton, and energy back transfer, respectively. A model is presented in which the Er-related electron trap shifts up in energy at higher pressure, increasing the activation energy to back transfer, but not affecting thermal dissociation of the bound exciton through hole emission. © 1997 American Institute of Physics. ͓S0021-8979͑97͒03912-1͔

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Section: B Effects On the Low Temperature Intensitymentioning

confidence: 99%

Photoluminescence studies of erbium-doped GaAs under hydrostatic pressure

Culp

Hömmerich

Redwing

et al. 1997

Journal of Applied Physics

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“…The energies of states Α and N were determined at low emission rates, when they were well separated from the trap C. The dominant trap C is clearly related to the well-known DX (Si). The trap D observed at a low concentration has been identified as E6 which is related to a complex associated with Ga vacancy and an oxygen atom [4] or an Al-O complex [5]. The traps Α and B well fit to unidentifled levels labelled E1 and E2 that were often observed in AlGaAs grown by MBE [6].…”

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confidence: 99%

Identification of Residual Impurities in Si-Doped MBE Grown GaAs

et al. 1995

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The changes of dopant vaporizatioii enthalpy in GaAs:Si grown by molecular beam epitaxy revealed the presence of residual donors related to group VI elements. This has been confirmed by deep level transient spectroscopy studies of AlGaAs:Si layers grown in the same MBE system. It is argued that a commonly observed deep trap labelled E2 is probably related to Te, Se or S. The measurements have been performed oii near-ideal Al Schottky barriers grown in situ by MBE. PACS numbers: 73.40.Νs, 71.55.Eq, 73.20.Hb It is generally accepted that Si is an almost ideal dopant for n-type GaAs grown by molecular beam epitaxy (MBE). At present the layer doping is still largely empirical and often, at low doping levels residual impurities disturb calculated dependences. Usually shallow acception can be readily identified by low temperature photoluminescence measurements. The chemical identities of shallow donors are more difficult to determine by simple methods, and resort has to be made to far-infrared photothermal ionization or very high resolution Zeeman photoluminescence studies.In this paper we discuss an unintentional codoping process during the growth of GaAs:Si by MBE. Thick epitaxial layers of GaAs were grown at 580°C on semi-insulating (001) oriented GaAs using the Riber 32Ρ MBE system, which has a background pressure < 1 x 10 -I 0 torr. High purity Ga (7Ν), As (7Ν) and Si (< 1012 cm-3 intrinsic) source materials were used. To achieve a full range of Si concentration the temperature of Si effusion cell was changed from 550°C to 1130°C, whereas those of Ga and As were held constant at 945°C and 2180C, respectively. The beam equivalent pressure As/Ga ratio was equal to 9.5. All layers were grown at constant rate 1 μm/h. Electrical properties of the epitaxial layers were characterised by Van der Pauw measurements. The effects of surface and (775)

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“…As evidenced by the spectra, a deep trap with the thermal activation energy of 0.78 eV below the conduction band was commonly present in the structures studied. On the basis of its thermal characteristic, the trap was found to be very similar to the trap at ΕC -0.76 eV observed in Al x Ga1-x As and identified as the main PL killer related to oxygen or the aluminium-oxygen comp lex [5]. We have found that the trap shows an accumulation at heterointerface as determined from its concentration proflle [6].…”

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confidence: 62%

Low Threshold Room Temperature AlGaAs/GaAs GRIN SCH SQW Lasers Grown by MBE

et al. 1996

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Low threshold room temperature AlGaAs/GaAs graded-index separate--confinement heterostructure single quantum well (GRIN SCH SQW) lasers were prepared by MBE. The influence of the growth temperature on the laser parameters was studied. Due to the high temperature MBE growth and the use of p-contact layer in the form of thin quasi-metallic beryllium layer significant reduction of the threshold current was achieved.PACS numbers: 85.30. De, 85.60.Jb, 73.20.Dx In the case of AlGaAs/GaAs GRIN SCH SQW lasers it has been found that the threshold current density, Jth, is critically dependent on growth parameters and shows W-shape dependence on the substrate temperature with minima at 375°C and 650°C [1] or at 740°C and 820°C according to other source [2]. The authors of both quoted papers [1,2] also showed that QW photoluminescence (PL) intensities were in excellent correlation with Jth when growth temperature was changed and the quality of the AlGaAs cladding layer played a more decisive role than the active layer quality. Contrary to that Weisbuch et al. [3] reported that the quality of QW was more Sensitive to the growth temperature than the AlGaAs cladding layer. Let us notice that the controversial results can be understood if we assume that an improvement in the quality of the heterointerface itself can be the explanation for the improvement of lasers parameters. In this paper we present results of systematic investigations of the influence of growth temperature on optical properties of GRIN SCH SQW stuctures and parameter8 of laser diodes made of these structures.The single quantum well laser stuctures grown on (100)-oriented n+-GaAs

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Photoluminescence killer center in AlGaAs grown by molecular-beam epitaxy

Cited by 83 publications

References 21 publications

Photoluminescence studies of erbium-doped GaAs under hydrostatic pressure

Photoluminescence studies of erbium-doped GaAs under hydrostatic pressure

Identification of Residual Impurities in Si-Doped MBE Grown GaAs

Low Threshold Room Temperature AlGaAs/GaAs GRIN SCH SQW Lasers Grown by MBE

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