Results Of Selected Area Electron Diffraction Pattern Research Articles

Atomic Arrangement and Formation Mechanism of c-Axis Oriented ZnO Thin Films Grown on p-Si Substrates

The X-ray diffraction (XRD) pattern for the ZnO films grown on Si (100) substrates indicates that the grown ZnO films have a strong c-axis orientation. The pole figure indicates that ZnO thin films have columnars with the grains of the [0002] crystallographic axis perpendicular to the Si (100) substrate, indicative of the random rotational orientations along the c-axis. Selected area electron diffraction pattern (SADP) of the ZnO/Si (100) heterostructures shows that the ZnO preferential oriented film is formed on the Si substrate. A possible atomic arrangement of the crystal structure and the formation mechanism of the c-axis orientated ZnO thin films grown on p-Si substrates are discussed on the basis of the XRD, the pole figure, and SADP results.

Dependence of the microstructural properties on the substrate temperature in strained CdTe (1 0 0)/GaAs (1 0 0) heterostructures

CdTe thin films were grown on GaAs (1 0 0) substrates by using molecular beam epitaxy at various temperatures. The bright-field transmission electron microscopy (TEM) images and the high-resolution TEM (HRTEM) images showed that the crystallinity of CdTe epilayers grown on GaAs substrates was improved by increasing the substrate temperature. The result of selected-area electron diffraction pattern (SADP) showed that the orientation of the grown CdTe thin films was the (1 0 0) orientation. The lattice constant the strain, and the stress of the CdTe thin film grown on the GaAs substrate were determined from the SADP result. Based on the SADP and HRTEM results, a possible atomic arrangement for the CdTe/GaAs heterostructure is presented.

Microstructural properties and atomic arrangements in GaN/sapphire and AlxGa1−xN∕AlN∕GaN∕sapphire heterostructures

Microstructural and atomic structure studies of GaN/sapphire and AlxGa1−xN∕AlN∕GaN heterointerfaces have been performed by using bright-field transmission electron microscopy (TEM) and selected area electron diffraction pattern (SADP) measurements. TEM and SADP results from the GaN/sapphire and the Al0.4Ga0.6N∕AlN∕GaN∕sapphire heterointerfaces showed that GaN epilayers and Al0.4Ga0.6N, AlN, and GaN active layers, respectively, had been grown on the sapphire substrates. The values of the strain and the stress in the Al0.4Ga0.6N, the AlN, and the GaN layers were determined. Possible schematic diagrams of the two heterostructures, as well as diagrams of the [21¯1¯0] projections of the GaN epilayer and the Al0.4Ga0.6N∕AlN∕GaN heterostructure, are presented based on the TEM and SADP results. These results can help improve the understanding of the microstructural properties of the strained AlxGa1−xN∕AlN∕GaN∕sapphire heterostructures for applications in the high-speed and high-power electronic devices.

Strain effects and atomic structures in highly lattice-mismatched InAs 0.6P 0.4/InP modulation-doped single quantum wells

Strain effects in highly lattice-mismatched InAs 0.6P 0.4/InP modulation-doped single quantum wells were investigated by the high-resolution transmission electron microscopy (HRTEM), the selected-area electron diffraction pattern (SADP), and the Raman scattering spectroscopy measurements. The HRTEM and the SADP measurements on the InAs 0.6P 0.4/InP single quantum wells showed that the InAs 0.6P 0.4 active layer was grown pseudomorphologically on the InP buffer layer in spite of highly lattice mismatch. The values of the horizontal and vertical strains and the horizontal stress of the InAs 0.6P 0.4 layer are - 1.9 × 10 -2, 2.1 × 10 -2, and - 16.26 × 10 -2 dyne cm −2, respectively. A possible crystal structure for the InAs 0.6P 0.4/InP single quantum well is presented based in the HRTEM and the SADP results. These results can help improve understanding the microstructural properties of strained InAs xP 1-x/InP modulation-doped single quantum wells.