The band-gap energy and the electron effective mass of In1−x−yGaxAlyAs lattice matched to InP have been determined as a function of Al content. From photoluminescence measurements we obtain Eg(eV) = (0.76±0.04)+(1.04±0.10)y+(0.87±0.13)y2. The electron effective mass is determined from the plasma frequencies measured with Raman scattering in n-type samples. Its compositional dependence is given by m* = (0.0427±0.0015)+(0.0683±0.0007)y.

We report the first direct demonstration of a strain-generated built-in electric field in a (111) oriented strained-layer heterostructure. We present a model which describes the accommodation of the misfit strain in a lattice-mismatched quantum well, and the resulting generation of a longitudinal electric field via the piezoelectric effect. On a (111)B GaAs substrate, we grew the quantum well in the intrinsic region of a p-i-n diode such that the strain-generated electric field in the quantum well opposes the weaker built-in electric field of the diode. Under reverse bias operation, photoconductivity measurements show a quadratic blue shift of the quantum well electroabsorption peaks, in contrast to the red shifts normally observed in the quantum-confined Stark effect. The measured blue shifts demonstrate an electric field strength of 1.7×105 V/cm, which agrees with theory to within the accuracy of the measured sample characteristics.

We have observed room-temperature exciton blue shift with applied voltage in a 〈111〉 In0.1Ga0.9As-GaAs p-i-n multiple quantum well modulator. We have also observed optically induced bistability in a symmetric self-electro-optic effect device circuit composed of these modulators. Very large (2.5:1) ratios of photocurrent were obtained with only 0–3 V applied bias.

We calculate the strain tensor components for (hhk)-oriented cubic materials with misfit-generated strain. We assume the strained layer to be free of crystalline defects, and derive the tensor elements via minimization of the crystal strain energy with the imposed constraint that the epitaxial film remains in registry with the substrate lattice. The strain components described, both in the crystalline basis and in the basis of the growing film, are written in terms of the lattice mismatch and the growth-axis Miller indices. We show that the accommodation of misfit-generated strain produces a tetragonal distortion for all (hhk)-grown layers, and use the above results to interpret x-ray diffraction data.

Epitaxial layers of p-type In1−x−yGaxAlyAs doped with Mn were grown by molecular beam epitaxy. The doping characteristics and electrical properties are studied using Hall measurements in the temperature range between 100 and 300 K. Secondary ion mass spectrometry (SIMS) was used to study Mn profiles and diffusion coefficients. The maximum hole concentration attainable at room temperature is relatively independent of the As flux and is found to decrease from 4×1018 for y=0 to 2×1016 cm−3 for y=0.48. The experimental results of the resistivity and Hall effect are used to determine the densities Na, Nd of acceptors and compensating donors and the activation energy. The acceptor activation energy Ea increases from 50 at y=0 to 200 meV at y=0.23. Ea is found to be independent of the hole concentration and the arsenic flux used during the molecular beam epitaxial growth. The hole mobility for hole concentration of ∼1017 cm−3 is about 140 cm2 V−1 s−1 and decreases with increasing y. SIMS measurements of the Mn profiles show that Mn diffusion is significant at temperatures 650 °C and above, but is insignificant under the growth condition at 493 °C. Abrupt junction and sharp Mn pulses (<0.15 μm wide) have been obtained. Mn surface segregation is negligible at growth temperatures above 500 °C.