Hideo Goto

Interface-Roughness Scattering in GaAs/AlxGa1-xAs Superlattices

The electron mobility limited by the interface-roughness scattering in a GaAs/AlxGa1-xAs superlattice is studied as a function of the period (the well width LW and the barrier thickness LB) and the temperature. If the superlattice period is short and the electronic states resemble that of the 3D state, the mobility is limited by the interface-roughness scattering at low temperatures and insensitive to the temperature, in good agreement with experimental results. Using a finite potential-barrier height, it is shown that the variation of the mobility as a function of the quantum well width LW is not so steep as that of the single-quantum-well structure assuming an infinite potential-barrier height.

Electrical properties of Sb-doped ZnSe grown by metalorganic vapor phase epitaxy

Abstract The Hall measurements were performed on Sb-doped ZnSe grown by metalorganic vapor-phase epitaxy. The hole concentration of 10 16 xa0cm, which is independent of the growth temperature, was obtained. The mobility of the ZnSe grown at 525°C is 27xa0cm 2 /Vs. The activation energy of acceptor in Sb-doped ZnSe is 600xa0meV, which is thought to be due to the Sb deep level.

VPE growth of ZnS incorporating indium on GaP

In the hetero-epitaxial growth of cubic ZnS on a GaP(100) substrate using an open-tube method with hydrogen gas, it was found that the incorporation of indium greatly improved the surface morphology of the ZnS epitaxial layer. The role of indium in the growth kinetics has been studied. The concentration of indium was estimated to be 1018-1019 cm-3. Photoluminescence measurements showed that the incorporation of indium reduced some of the defects that had caused emission peaking at 470 nm.

Photoacoustic spectra of Sb-doped ZnSe

Photoacoustic (PA) spectra were made on Sb-doped ZnSe samples grown by metalorganic vapor phase epitaxy (MOVPE). The samples deposited at a low temperature under irradiation show the PA spectrum with a sharp edge near the band gap and with three distinct peaks. From the Sb flow rate dependence of PA peaks, two of them seem to be related to Sb impurities. Non-doped sample shows only one peak, which is tentatively ascribed to the deep level associated with Se defects.

Metalorganic Vapor Phase Epitaxy of Sb-Doped ZnSe

The Sb-doped ZnSe was grown on (100)GaAs substrate by using the Metalorganic Vapor Phase Epitaxy method in atmospheric pressure in order to obtain a p-type ZnSe film. The C-V measurement of the Sb-doped ZnSe layer suggests a p-type conduction. The maximum space charge concentration obtained was 1.5×1016 cm-3. The acceptor level of Sb, which was estimated from the photoluminescence spectrum, was found to be 69 meV.

Thermodynamical Analyses and Luminescence Properties of Vapor-Grown ZnSxSe1-x

Vapor phase transport analyses are presented regarding the epitaxial growth of ZnSxSe1-x on GaP. It has been predicted from a thermodynamical calculation and experimentally confirmed that the solid composition x can be controlled over a wide range by varying the source and/or the substrate temperature. The photoluminescence of epitaxial layers of ZnSxSe1-x (0.44≤x≤0.92) grown on GaP exhibits a strong edge emission at room temperature, showing that the epitaxial layers are of high quality.

Antimony Treatment Effect on Cd1-xMnxTe Growth on GaAs by Metal-Organic Vapor Phase Epitaxy

A heteroepitaxial film of Cd1-xMnxTe has been grown on a (100)GaAs substrate by metal-organic vapor phase epitaxy. It is shown that a high quality Cd1-xMnxTe film can be grown on the GaAs substrate by pretreating the GaAs substrate with triethyl antimony at 650°C. The best full width at half maximum of the X-ray diffraction peak of the Cd1-xMnxTe film (x=0.12) obtained was 650 arc sec. The effects of the triethyl antimony on the film quality of Cd1-xMnxTe are discussed.

Photoluminescence Decay Properties of Indium Doped ZnS

The photoluminescence decay properties of indium-doped ZnS thin films grown epitaxially on (100) GaP were investigated. Three exponential components were found in the decay curves, of which the time constants were of the order of 1, 10 or 100 µs at room temperature. Upon increasing the In concentration, the time constants increased. By lowering the temperature the photoluminescence decay became faster, and at low temperatures the time constant was insensitive to the temperature. The results can be well described by the three-level model of Di Bartolo. It could be shown that the photoluminescence originated from the trapping-limited D-A pair emission, and that the decay properties are determined mainly by the non-radiative recombination probabilities which depend on the In concentration.

MOVPE growth and characterization of Mn-doped ZnSe films

Abstract Mn-doped ZnSe was epitaxially grown on GaAs (0xa00xa01) single crystals by using MOVPE method. PL spectra taken at room temperature show orange emission peaked at 580xa0nm for all Mn-doping levels. However, the peaks of PL spectrum at 30xa0K were 550xa0nm for low levels of Mn-doping and 630xa0nm for high levels of Mn-doping. From PL and PLE experiments, the emission bands peaked at 550 and 630xa0nm seem to be due to the transition from 4 T 2 to 6 A 1 of 3d electron of the Mn atom and that from 4 T 1 to 6 A 1 , respectively.

Deep levels in Sb-doped ZnSe fabricated by metalorganic vapor-phase epitaxy

Abstract Sb-doped ZnSe samples were deposited on the (001)GaAs substrate by metalorganic vapor-phase epitaxy (MOVPE). Isothermal capacitance transient spectroscopy (ICTS) and spectral analysis of deep-level transient spectroscopy (SADLTS) were used to characterize deep levels of Sb-doped ZnSe. The p-type sample grown by MOVPE at 490°C in the darkness shows three ICTS peaks. Three deep levels were observed in the N-doped ZnSe deposited by MOVPE. Using the SADLTS, we can estimate the activation energy and the capture-cross section distributions of that hole traps. We also examined samples that were photoassist-deposited at lower temperature. The non-doped ZnSe thin films were also measured to check the effects of light irradiation during the deposition. We could get only n-type samples and the light irradiation generates the new level of the electron traps. Sb doping generates other new levels. The levels that correspond to trap E1 in the light-irradiated Sb-doped samples are constructed from two adjacent levels in SADLTS, and one new level near trap E1 can be observed in SADLTS.