Molecular‐beam epitaxy of CdxHg1−xTe at D.LETI/LIR

The structural and electrical properties of (lOO) Hgt_xCdxTe epilayers grown by molecular beam epitaxy have been systematically investigated for different HglTe flux ratios. The hillock density, electron concentration and the electron mobility depend strongly on the HglTe flux ratio. A minimum in the hillock density correlates well with the highest mobilities and the lowest concentrations. As is well known electrical properties are strongly influenced by structural defects. Structural defects such as twins and defects due to nonstoichiometry can be largely reduced by optimizing the HglTe flux ratio. It is shown that an optimum HglTe flux ratio exists within a narrow range between 270 and 360 at the growth temperature of 180 ·C, in contrast with the larger range of the HglTe flux ratio over which single crystalline growth could be maintained. The difficulties encountered in the x value determination from normal transmission curves, i.e., from Eo(x), due to the Burstein-Moss shift are discussed. In order to overcome these difficulties, the x values of the Hgt_xCdxTe epilayers were also determined fromEt (x). A calibration of Et (x) resulted in small but significant discrepancies with the literature. Extrinsic As doping using the ~ doping technique is demonstrated and a very high atomic sheet density of 1.2 X 1013 cm -2 is obtained..

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“…(1). The discrepancy between the x values is within experimental uncertainty (±0.OO2 and ±0.004 for El and Eo.…”

Section: A Optical Measurements and X Value Determinationmentioning

confidence: 75%

Molecular beam epitaxial growth and evaluation of intrinsic and extrinsically doped Hg0.8Cd0.2Te on (100) Cd0.96Zn0.04Te

Becker

Bicknell-Tassius

et al. 1993

Journal of Applied Physics

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“…Similar polycrystalline growth and twinning within the defect region have been reported on II-VI and III-V materials systems. 5 The cross-sectional profiles of all six defects studied are similarly rounded at the bottom. Additionally, TEM images and diffraction patterns indicate that the dark contrast near the bottom is due to the absence of material.…”

Section: Resultsmentioning

confidence: 94%

Morphological defects of molecular beam epitaxy-grown CdTe and CdSeTe on Si

Campo

Hierl

Hwang

et al. 2005

Journal of Elec Materi

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For the first time, focused ion beam milling, secondary electron microscopy, and transmission electron microscopy were used to examine in depth morphological defects during epitaxial growth of CdTe and CdSeTe on Si. Contrary to the literature regarding the formation of morphological defects at the epi/ substrate interface, the present defects appear to originate from either the CdTe/CdSeTe interface or 3-4 µm above the CdTe/Si interface where the growth was interrupted and the substrate temperature was temporarily raised. This suggests a correlation between defect nucleation and either shutter movement or growth interruption.

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“…The hillocks we observe here are not the same as those reported on (100) HgCdTe grown by MBE. 3,4 Those hillocks are discrete with only some of the localized defects corresponding to the discrete pyramidal hillocks shown by TEM plan view' and optical microscopy. 4 Figure 5a is a cross section TEM image of a p-layer grown on an n-layer from a different sample, which in this case does not show twining.…”

Section: Resultsmentioning

confidence: 99%

“…2 Hillock formation, observed during the growth in the (100) orientation, is also twin-related. 3,4 The existence of microstructual defects decreases the device quality. Obtaining twin-free n-p-n HgCdTe layers is Transmission electron microscopy (TEM) was used to evaluate the microstructure of molecular beam epitaxy (MBE) grown (211)B oriented HgCdTe films.…”

Section: Introductionmentioning

confidence: 99%