Showing papers by "Eric Tournié published in 1995"
TL;DR: In this article, the initial plastic relaxation of highly mismatched layers grown along GaAs is governed by the growth mode, and it is shown that when InAs are forced to grow in a two-dimensional (2D) mode, only pure edge-type dislocations are generated and they are located exactly at the epilayer/substrate interfacial plane.
Abstract: Using cross‐section and plan‐view transmission electron microscopy we demonstrate that the initial plastic relaxation of highly mismatched layers grown along [100] is governed by the growth mode. During MBE growth of InAs on GaAs in the Stranski‐Krastanov (SK) mode, 60o ‐type dislocations are generated at the island edges and then glide to the interface to relieve the strain. The resulting interfacial microstructure consists of an inefficient arrangement of misfit dislocations. On the other hand, when InAs is forced to grow in a two‐dimensional (2D) mode, only pure edge‐type dislocations are generated and they are located exactly at the epilayer/substrate interfacial plane. These results are explained by a different dislocation nucleation mechanism imposed by the planar morphology of the highly strained film.
65 citations
TL;DR: In this paper, two classes of non-reactive and reactive surfactants effective during homoepitaxy and hetero-epitactic, respectively, are presented.
40 citations
TL;DR: In this paper, the InAs layers were grown by molecular beam epitaxy using different growth conditions, which allowed them to change the growth mode from the typical Stranski-Krastanov to a layer-by-layer mode.
22 citations
TL;DR: In this paper, temperature-dependent photoluminescence (PL) spectroscopy between 9 K and 300 K Zn1−xCdxSe/ZnSe strained-layer quantum wells (QWs) with Cd contents ranging between 12% and 19% and QW thickness between 9 and 175 A, with confinement energies up to 220 meV.
Abstract: We investigate by temperature‐dependent photoluminescence (PL) spectroscopy between 9 K and 300 K Zn1−xCdxSe/ZnSe strained‐layer quantum wells (QWs) with Cd contents ranging between 12% and 19% and QW thicknesses between 9 and 175 A, i.e., with confinement energies up to 220 meV. In the whole temperature range the PL spectra are dominated by E1‐HH1 free‐exciton recombinations. Between 9 and 300 K the intensity of this line is reduced by three to four orders of magnitude while transitions involving excited states progressively emerge. An analysis of the thermal quenching of the PL intensity reveals that for all confinement energies the escape of excitons out of the QWs is the mechanism responsible for this quenching near 300 K.
20 citations
TL;DR: In this article, high-resolution and diffraction contrast electron microscopy measurements show the presence of different contrast zones in the epilayers of lattice matched AlxIn1−xAs/InP and GayIn 1−yAs/inP epilayer grown by molecular beam epitaxy on InP(100) substrate.
Abstract: In this work we report on transmission electron microscopy and high‐resolution x‐ray diffractometry studies of lattice matched AlxIn1−xAs/InP and GayIn1−yAs/InP epilayers grown by molecular beam epitaxy on InP(100) substrates. High‐resolution and diffraction contrast electron microscopy measurements show the presence of different contrast zones in the epilayers. The analysis of high‐resolution x‐ray diffraction measurements and computer simulations ascribe these zones to the presence of a compositional gradient in the epilayers. A comparison among investigated samples grown under slightly different growth conditions combined with an analysis of the crystal defects is presented. Growth‐induced small variations in the chemical composition of the epilayer can produce differences in the structural quality of the epitaxial layer. Finally, a few monolayers thick and highly strained film of InAsP, is observed in all investigated samples at the substrate/epilayer interface. The formation of this interface layer i...
12 citations
TL;DR: In this article, preliminary results about MBE growth and characterization of ZnSe-based alloys and multi-quantum wells (MQW) are presented, and several Zn1−xCdxSe/ZnSe MQWs are grown.
Abstract: Preliminary results about MBE growth and characterization of ZnSe-based alloys and multi-quantum wells (MQW) are presented. Undoped ZnSe and Zn1−xCdxSe compounds exhibiting structural and optical properties, comparable to the best results previously published, are grown. RHEED intensity oscillations are observed during ZnSe and Zn1−xCdxSe growth. Several Zn1−xCdxSe/ZnSe MQWs are grown. RHEED intensity analysis is used to accurately control the well thicknesses. The MQWs produce very intense and sharp photoluminescence peaks. The sharpness of interfaces is confirmed by X-ray analysis. Cl-doped ZnSe epilayers with doping levels at 77 K ranging from 6 × 1015 to 6 × 1018 cm−3 are obtained.
6 citations
TL;DR: In this article, a simple model that leads to a qualitative understanding of the experimental observation is presented, which reveals mono-and bilayer high steps and islands, reflecting a layer-by-layer growth with the participation of both at the same time.
4 citations
TL;DR: In this paper, the authors reported on time-integrated and time-resolved optical experiments performed on a 26 A thick Zn0.85Cd0.15Se/ZnSe quantum well, for temperatures in the 10-200 K range.
Abstract: We report on time-integrated and time-resolved optical experiments performed on a 26 A thick Zn0.85Cd0.15Se/ZnSe quantum well, for temperatures in the 10–200 K range. Excitation spectroscoy allows an estimation of the relative valence band offset, which is found to be 10%. From the temperature variation of the decay time of the photoluminescence performed reasonantly on the e1h1 excitonic transition, we deduce that the main non-radiative mechanism is the heavy-hole thermal escape out of the well.
3 citations
TL;DR: In this article, structural and optical properties of (In,Ga)As/GaAs heterostructures induced by the low symmetry of the [311]A orientation were investigated.
2 citations