Double Heterostructure Samples Research Articles

Atomic scale analysis of MOVPE grown heterostructures by X-ray crystal truncation rod scattering measurement

The origin of the X-ray CTR scattering have been described in brief in order to make it clear why the X-ray CTR scattering measurement can reveal the interface structure. Then, some examples of the results obtained by the X-ray CTR scattering measurement have been shown. The distributions of group-V and III atoms in InP/GaInAs/InP double-heterostructure samples have mainly been discussed. The change of the distribution of As at the interface with the change of H 2 -purge time has been quantitatively shown at an atomic scale by the X-ray CTR scattering measurement, which has demonstrated the high resolution and significance of the X-ray CTR scattering measurement in the investigation of the III–V compound semiconductor heterostructures. The distribution of group-III atoms has also been investigated by the X-ray CTR scattering measurement. The results have suggested that the interface has not been so abrupt as expected, and it has been more difficult to control the distributions of group-III atoms than group-V atoms. The results have shown how important the observation by the X-ray CTR scattering has been to understand the interface structure.

Evaluation of the properties of hydrogenated InP/InGaAsP double heterostructure waveguides

The potentiality of H passivation in InP-based photonic device technology was investigated by evaluating the properties of hydrogenated InP (Zn)/InGaAsP double heterostructure (DHS) waveguide (WG) samples. Subsequent to plasma exposure, conventional photoluminescence (PL) measurements were employed to monitor the optical quality, and Fabry-Perot damping oscillation measurements at ~ 1.55μm to evaluate the propagation losses. We report here that hydrogenation significantly improves the optical quality of DHS samples and further brings about an efficient (90%) neutralization of Zn acceptors in the upper p-InP confinement layer, and to a lesser extent, also of those that are involuntarily introduced into the nominally undoped InGaAsP quaternary (Q) guiding layer. These two features are shown to be profitable in photon device technology as they can be engineered to reduce propagation losses (due to free-carrier absorption) in the DHS buried WG structures.

Temperature dependence of the minority carrier lifetime in GaAs/AlGaAs double heterostructures

We have studied the photoluminescence decay time in a series of high quality GaAs/AlGaAs double heterostructure samples, grown by liquid phase epitaxy, with different p-type doping. We have compared the experimentally observed decay time as a function of temperature from 100 to 700 K, with a complete calculation of the radiative recombination rate, including the temperature dependence of the reabsorption factor. We conclude that the observed decay time is well explained by a dominating radiative recombination up to temperatures of about 500 K. The internal quantum efficiency is hence close to unity. At higher temperatures we observe a deviation from the expected values for the radiative recombination, attributed to a nonradiative recombination channel.