AlInAs Band Gap Modulations Observed by Tem and Optical Measurements

Abstract

At a low MBE growth temperature (400°C), an anisotropic composition modulation has been observed by Transmission Electron Microscopy (TEM) on AIlnAs layers. Optical measurements have been performed on these samples and compared with classical AllnAs grown at 530°C. We show the clustering “organization” on the low temperature layers and we propose some hypothesis to explain the composition modulation effects on the AlInAs optical properties.

The Nature and Origin of Lateral Composition Modulations in Short-Period Strained-Layer Superlattices

“…The InAIAs buffer layer is not necessarily homogeneous since several forms of compositional modulation have been observed in MBE In.AIAs epitaxial layers [19][20][21]. In our InAlAs buffer layers a very weak lateral composition modulation was observed, in plan-view TEM studies, along [110] with a wavelength of =9 nm similar to that reported previously [20,21] in lMBE InAlAs layers grown at lower temperatures. The elastic stresses associated with this compositional modulation could influence the nucleation of the first InAs layer of the SPS [18].…”

Steplike Lineshape of Low Temperature Photoreflectance Spectra of InAlAs

“…Results are published elsewhere [8]. The half widths at half maximum of PL peaks are rather large when compared with the theoretical limits for alloy scattering in this system and with the best experimental result which is about 2.8meV at 4K [9].…”

Application of photoreflectance spectroscopy to the study of interface roughness in InGaAs/InAlAs heterointerfaces

“…The AlInAs PR feature is very large, indicating the modulation composition of this alloy. 13 The PR transitions corresponding to the quantum confined levels in the quantum well are fitted using the first derivative functional form ͑FDFF͒ of the dielectric function, which is appropriate in the case of confined systems 14…”