Development of MBE II–VI Epilayers on GaAs(211)B

Jacobs, R. N.; Nozaki, C.; Almeida, L. A.; Jaime-Vasquez, M.; Lennon, C. M.; Markunas, J. K.; Benson, D. K.; Smith, Paul J.; Zhao, Wenfeng; Smith, David J.; Billman, C.; Arias, J.; Pellegrino, Joseph G.

doi:10.1007/s11664-012-2218-z

Cited by 21 publications

(6 citation statements)

References 14 publications

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“…These values, indicative of good surface quality, are in quite good agreement with those reported in the literature. 28 In Fig. 2, triangle shapes of the etch pits, usually observed in CdTe epilayers, 9 are clearly visible in the SEM images.…”

Section: Resultsmentioning

confidence: 90%

“…These surface defects are mainly formed from discrete voids and tellurium precipitates. 28 The RMS surface roughness values of the specimens of CT102, CT103, and CT105 were estimated to be 5.3 nm, 5.5 nm, and 4.4 nm (Table II), respectively. These values, indicative of good surface quality, are in quite good agreement with those reported in the literature.…”

Section: Resultsmentioning

confidence: 99%

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Identifying threading dislocations in CdTe films by reciprocal space mapping and defect decoration etching

Polat

Bilgilisoy

Arı

et al. 2018

Journal of Applied Physics

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We study threading dislocation (TD) density of high-quality cadmium telluride (CdTe) layers grown on a (211) oriented GaAs substrate by molecular beam epitaxy. High-resolution X-ray diffraction was performed to calculate the density of screw-type TDs by measuring the broadening of the asymmetrical (511) Bragg reflections of CdTe epilayers. In addition, total TD densities were determined by the Everson-etching method and were compared with screw TDs. Our results show that the total TD densities in CdTe films were dominated by those with screw character. The screw component TDs are estimated to account for more than 90% of the total TD density.CdTe layers grown at a thickness of less than 3.0 lm typically exhibit the screw TD densities in the 10 6 cm -2 and 10 7 cm -2 range. It can be noted that as the nucleation temperature increases, i.e., !222 C, both the area density of TDs with the screw component of the CdTe films and the total TD density are roughly four times larger than those of the epilayer grown at the nucleation temperature of 215 C. Furthermore, we discuss the influence of the II/VI flux ratio on the density of threading dislocations. The contribution of screw TDs to the total TD density showed a significant decrease in roughly 30% in the case of a high II/VI flux ratio. We further examine the reciprocal space maps in the vicinity of the (422) reflections.

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Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Identifying threading dislocations in CdTe films by reciprocal space mapping and defect decoration etching

Polat

Bilgilisoy

Arı

et al. 2018

Journal of Applied Physics

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“…Composite CdTe(211)B/GaAs(211)B substrates have recently attracted renewed attention because of the ready availability of large-area GaAs(211)B wafers as well as the ease of their surface preparation relative to Si substrates due to the easier in situ surface oxide removal. 2 Several cycles of annealing were used during deposition of the thick CdTe buffer layers in efforts to reduce the overall density of threading dislocations, and TEM cross-section observations confirmed that a large decrease had occurred upon moving away from the region of the CdTe/GaAs interface.…”

Section: Cdte/gaas(211)b Substratementioning

confidence: 90%

“…1 Thus, epitaxial growth of MCT on large-area, low-cost substrates, rather than bulk, lattice-matched cadmium zinc telluride, is a highly active field of current research. 2,3 Similarly, CdTe (band gap 1.44 eV) and ZnTe (band gap 2.26 eV) represent potentially viable candidates for photodetectors or multijunction solar cells, but highquality crystalline material is considered to be essential to avoid degradation in device performance. Developing a successful strategy for defect reduction during epitaxial growth of these and other II-VI materials, given the likely lattice mismatch with any potential substrate and inevitable differences in their thermal expansion coefficients, becomes a challenging task.…”

Section: Introductionmentioning

confidence: 99%

Atomic-Scale Characterization of II–VI Compound Semiconductors

Smith

2013

Journal of Elec Materi

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Alloys of II-VI compound semiconductors with suitable band gap selection potentially provide broad coverage of wavelengths for photodetector applications. Achievement of high-quality epitaxial growth is, however, essential for successful development of integrated photonic and optoelectronic devices. Atomic-scale characterization of structural defects in II-VI heterostructures using electron microscopy plays an invaluable role in accomplishing this goal. This paper reviews some recent high-resolution studies of II-VI compound semiconductors with zincblende crystal structure, as grown epitaxially on commonly used substrates. Exploratory studies using aberration-corrected electron microscopes are also briefly considered.

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“…2 Among these, Si and GaAs are the most promising, with tremendous progress having been made in recent years. 3,4 They are low cost and large area, and have many fewer surface defects compared with CdZnTe. Surface dislocation density values of Si, GaAs, and CdZnTe substrates are $100 cm À2 , $10 3 cm…”

Section: Introductionmentioning

confidence: 99%

Characterization of CdTe Growth on GaAs Using Different Etching Techniques

Bilgilisoy

Özden

Bakali

et al. 2015

Journal of Elec Materi

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CdTe buffer layers which were grown on (211)B GaAs by molecular beam epitaxy were subjected to two different etch treatments to quantify the crystal quality and dislocation density. The optical properties and thicknesses of the samples were obtained by ex situ spectroscopic ellipsometry. The surface morphologies of the CdTe epilayers were analyzed by atomic force microscopy, scanning electron microscopy, and Nomarski microscopy before and after chemical etching. We compare the triangle-and trapezoid-shaped etch pits due to the Everson and Nakagawa etch solutions, respectively. Measured etch pit density (EPD) values of triangle etch pits were found in the 8 9 10 7 cm À2 to 2 9 10 8 cm À2 range, and trapezoid-shaped etch pits were found in the 1 9 10 7 cm À2 to 7 9 10 7 cm À2 range for samples with thicknesses <2 lm.

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Development of MBE II–VI Epilayers on GaAs(211)B

Cited by 21 publications

References 14 publications

Identifying threading dislocations in CdTe films by reciprocal space mapping and defect decoration etching

Identifying threading dislocations in CdTe films by reciprocal space mapping and defect decoration etching

Atomic-Scale Characterization of II–VI Compound Semiconductors

Characterization of CdTe Growth on GaAs Using Different Etching Techniques

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