Molecular beam epitaxy of Zn(Se,Te) alloys and superlattices

Turco-Sandroff, F. S.; Nahory, R. E.; Brasil, M. J. S. P.; Martin, R. J.; Beserman, R.; Farrow, L. A.; Worlock, J. M.; Weaver, Amanda L.

doi:10.1016/0022-0248(91)91077-n

Cited by 24 publications

(5 citation statements)

References 9 publications

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“…Due to the preferential incorporation of Se over Te, the Se/Te ratio in the solid was difficult to control by adjusting the Se/Te flux ͑or BEP͒ ratio. 4 However, the composition of ZnSe 1Ϫx Te x could be precisely controlled by adjusting the Se/Zn BEP ratio, with an excess of Zn at the surface. The layers were grown under Te-rich conditions with the Te BEP about 1.5 times larger than that of Zn.…”

Section: Department Of Chemistry City College and Graduate Center Ofmentioning

confidence: 99%

Molecular-beam epitaxy growth and nitrogen doping of ZnSe1−xTex alloys grown on InP substrates

Lin

Bing

Guo

et al. 1999

Applied Physics Letters

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High-quality ZnSe1−xTex alloys spanning the entire compositional range have been grown by molecular-beam epitaxy. Good compositional control can be obtained by adjusting the beam equivalent pressure ratio of Se to Zn during growth. Double-crystal x-ray rocking curves with full widths at half maximum as narrow as 70 arcsec were obtained suggesting excellent crystalline quality. The p-type doping with nitrogen of ZnSe1−xTex alloys having Te contents from 0% to 100% has been systematically studied. The free hole concentration increases from 1017 to 1019 cm−3 as the Te content increases from 12% to 40%. The N-doped ZnSeTe lattice matched to InP has a free hole concentration of 2×1019 cm−3. This highly doped material was used as the p-type ohmic contact layer in light-emitting diodes made from ZnCdMgSe/ZnCdSe quantum-well structures grown on InP substrates that emit in the red, green and blue regions.

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Section: Department Of Chemistry City College and Graduate Center Ofmentioning

confidence: 99%

Molecular-beam epitaxy growth and nitrogen doping of ZnSe1−xTex alloys grown on InP substrates

Lin

Bing

Guo

et al. 1999

Applied Physics Letters

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“…This preferential incorporation of Se over Te is owing to the larger partial vapor pressure for Se than that of Te at growth temperature allowing for the replacement of adsorbed Te by selenium atoms. 26 Only the peaks corresponding to ͑002͒ and ͑004͒ Bragg reflections of ZnSe and GaAs were detected in x-ray / 2 diffractograms, this indicates the epitaxial relation between the layers and the GaAs͑001͒ substrate. Thus, a very low composition of tellurium in the epilayer grown under thermodynamic conditions of ICSS is expected.…”

Section: Resultsmentioning

confidence: 96%

“…The value of E =2 / ͑1−͒ =2C 12 / C 11 can be determined from the Poisson ratio, , or from the elastic stiffness coefficients, C 11 and C 12 , of the epilayer. 9,26 This indicates the low density of structural defects in the pseudomorphic epilayer. For the purpose of calculations, the dependence of E with Te composition could be neglected, and for low Te incorporation it is a good assumption to take E = 1.20.…”

Section: Resultsmentioning

confidence: 99%

Growth of ZnSe(1−x)Tex epilayers by isothermal closed space sublimation

Larramendi

Z-B

Woggon

et al. 2010

Journal of Applied Physics

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ZnSe ͑1−x͒ Te x ͑x ϳ 0.06͒ epilayers were grown on GaAs͑001͒ substrates at 350°C by isothermal closed space sublimation ͑ICSS͒ technique. The epitaxial growth was performed in low-pressure helium atmosphere ͑ϳ0.1 mbar͒ by sequential exposures of the substrate to vapors of a solid solution of selenium-tellurium and elemental zinc. The use of a mixed source is proposed in order to regulate the partial vapor pressure of the constituents by composition. Strain and composition of the ZnSe ͑1−x͒ Te x epilayers were extracted from high resolution x-ray reciprocal space mapping. Structural investigations show a reasonably good crystalline quality of the epilayers. Good reproducibility of composition and control of thickness were obtained although atomic layer epitaxy regimen was not achieved. A growth rate of 1.3 monolayers/cycle was ascribed to multilayer adsorption and the existence of an efficient transport of SeTe in graphite under thermodynamic conditions of ICSS. Both Raman and photoluminescence characterizations suggest the existence of random alloy epilayers with larger composition disorder in the mesoscopic scale than those obtained by molecular beam epitaxy.

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“…X-ray diffraction measurement was performed to determine the composition of CdSexTe,., epilayers using Vegard's law. Reflection highenergy electron diffraction (RHEED) patterns were observed during growth.Several researchers succeeded the composition control of ZnSe,Te,., films by molecular beam epitaxy (MBE) [2,3]. Yao reported that the composition x is equal to the beam intensity ratio of Se to Zn (JS$Jzn) when the beam intensity of Te is larger than that of Se.…”

mentioning

confidence: 99%

“…Several researchers succeeded the composition control of ZnSe,Te,., films by molecular beam epitaxy (MBE) [2,3]. Yao reported that the composition x is equal to the beam intensity ratio of Se to Zn (JS$Jzn) when the beam intensity of Te is larger than that of Se.…”

mentioning

confidence: 99%

Growth conditions in molecular beam epitaxy for controlling CdSeTe-epilayer composition

Matsumura

Sakamoto

Saraie

International Conference on Molecular Bean Epitaxy

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CdSe,Te,.,/ZnSe quantum-dots structures have the large conduction and valence band offset at an appropriate composition and is expected to be a highly-efficient light-emitting material in green region. However, to our knowledge, there have been very few reports on CdSeTe epilayers [I]. Composition control of II-VIxVI.x mixed crystals is difficult because the vapor pressures of VIth elements are high. In this report, the gowth conditions were studied for controlling CdSeTe-epilayer composition.The substrates used were GaAs(100). Elemental Cd, Se and Te were used as source materials. The growth temperature was 300°C. X-ray diffraction measurement was performed to determine the composition of CdSexTe,., epilayers using Vegard's law. Reflection highenergy electron diffraction (RHEED) patterns were observed during growth.Several researchers succeeded the composition control of ZnSe,Te,., films by molecular beam epitaxy (MBE) [2,3]. Yao reported that the composition x is equal to the beam intensity ratio of Se to Zn (JS$Jzn) when the beam intensity of Te is larger than that of Se. This situation means that Se atoms are preferentially incorporated into ZnSeTe epilayers. This is due to larger heat of formation of ZnSe (39.0 kcalhol) than that of ZnTe (28.1 kcalhol) [4]. In case of MBE growth of CdSe,Te,.,, however, the composition x was not equal to the beam intensity ratio of Se to Cd (JsJJcJ when JTe is larger than J-, and also the composition I-x was not equal to the beam intensity ratio of Te to Cd (JTJJc,J when J,, is larger than J, . These results indicate that Se atoms (Te atoms in the latter case) are not preferentially incorporated into CdSeTe epilayers. The competition for incorporation of the Se and Te adatoms occurs on the growing surface.Turco-Sandroff reported that composition was controlled by growing ZnSeTe epilayers on the Zn-stabilized surface. Then, we grew CdSe,Te,., epilayers on the Cd-stabilized surface, which was confirmed by the ~(2x2) reconstruction patterns of RHEED. The composition x of the CdSe,Te,., epilayers could be well controlled by the beam intensity ratio of JS$(Js+JTe) as shown in Fig. 1. This situation is successfully explained by a simple growth model under following assumptions. (1) The two kinds of VIth impinging atoms on the IInd-atom-exposed surface are adsorbed at sticking probabilities of each atom. (2) No competition occurs for incorporation of two kinds of VIth atoms on the Cd-exposed surface. The ratio of the sticking probability of Se (b) to Te (kTJ was calculated to be 0.1 by the above-mentioned growth model. ks, is smaller than kTe because the vapor pressure of Se is very high and the heat of formation of CdSe (32.6 kcal/mol) is small compared to that of ZnSe.

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Molecular beam epitaxy of Zn(Se,Te) alloys and superlattices

Cited by 24 publications

References 9 publications

Molecular-beam epitaxy growth and nitrogen doping of ZnSe1−xTex alloys grown on InP substrates

Molecular-beam epitaxy growth and nitrogen doping of ZnSe1−xTex alloys grown on InP substrates

Growth of ZnSe(1−x)Tex epilayers by isothermal closed space sublimation

Growth conditions in molecular beam epitaxy for controlling CdSeTe-epilayer composition

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