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Articles you may be interested inEffects of interface donors on far infrared photoresponse at cyclotron resonance in a (AlGa)As/GaAs heterojunction J.Effects of carrier confinement in graded AlGaAs/GaAs heterojunctions Appl. Phys. Lett. 45, 739 (1984); 10.1063/1.95381 Measurements of refractive index step and of carrier confinement at (AlGa)As-GaAs heterojunctionsAn unusual new line has been observed in the low-temperature photoluminescence spectrum of GaAsl AIGaAs epilayers grown by liquid-phase epitaxy, which represents a unique probe of the heterointerface. A very strong, broad and asymmetric line is seen, with peak energy ranging from that of the bound exciton to that of the shallowest acceptor, increasing roughly linearly with the logarithm of the excitation power. The intensity is seen to exhibit a very strong temperature dependence as the temperature is varied from 1.4 K up to about 20 K where the line falls below the background luminescence intensity. Intensity and energy dependence of the luminescence as a function of the Al mole fraction on one side of the junction is also investigated. By employing a novel step-etching technique, this transition is shown to originate from the GaAsl AIGaAs heterojunction. A qualitative model is proposed to explain the observed data.

An unusual new line has been observed in the 1.4-K photoluminescence spectrum of GaAs/AlGaAs epilayers grown by liquid phase epitaxy. A very strong, broad, and asymmetric line is seen, with peak energy ranging from the bound exciton to the shallowest acceptor, increasing roughly linearly with the logarithm of the excitation power. By employing a novel step-etching technique, this transition is shown to originate from the GaAs/AlGaAs heterojunction. A qualitative model is proposed to explain the observed data.

The concentration profiles of carboxy-terminated polystyrene chains in the melt grafted onto oxidecovered silicon substrates were measured using secondary-ion mass spectroscopy. The grafting density increased with temperature and an enthalpy of +7.4 kcal/mole was deduced for the grafting reaction, SiOH + /?(COOH)^/?(COOSi) + H 2 0. Relatively high grafting densities ( 10 mg/m 2 . An equilibrium constant for the grafting reaction incorporating entropy is discussed.

Epitaxial AlxGa1−xAs structures whose compositions x vary continuously with thickness according to a given input function have been grown by chemical-beam epitaxy under closed-loop ellipsometric control. 200- and 500-Å parabolic quantum wells analyzed by photoreflectance and secondary-ion mass spectrometry, respectively, show that actual compositions follow target values to within 0.02 in x. Growth of the 200-Å profile was controlled using compositions ellipsometrically determined for the outermost running 3.1 Å (∼1 monolayer) of depositing material.