InAs layers were deposited on glass substrates by molecular-beam deposition at substrate temperatures of 180 -240 C at As/ In beam equivalent pressure (BEP) ratios of 3 -30. X-ray diffraction (XRD) patterns indicated that the InAs layers are polycrystalline and are more preferentially textured in the (111) plane when deposited at higher temperatures and lower As/In BEP ratios. Room-temperature Hall effect measurement showed that the films deposited at an As/In BEP ratio of 30 exhibit n-type conduction with electron concentrations of approximately 3 Â 10 18 cm À3 , being almost independent of substrate temperature. With decreasing As/In BEP ratio from 30 to 3 at a fixed substrate temperature of 240 C, the electron concentration decreased to 1:5 Â 10 18 cm À3 and the electron mobility increased to 610 cm 2 /(VÁs). Preliminary results of the deposition on plastic substrates showed an electron mobility of 460 cm 2 /(VÁs) when the layer was deposited at 280 C at an As/In BEP ratio of 30.

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Refractive index has been determined from reflectance measurements at 77‐300 K for Tlx Ga1–x As samples with x ≤ 0.077 prepared by low‐temperature molecular‐beam epitaxy. A very high refractive index of around 4.5 at room temperature in the transparent wavelength region has been revealed for Tlx Ga1–x As with x = 0.077. The temperature coefficient of the refractive index was found to increase with Tl content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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