Dislocation and Elastic Strain in an InN Film Characterized by Synchrotron Radiation X-Ray Diffraction and Rutherford Backscattering/Channeling

摘要

Dislocation information and strain-related tetragonal distortion as well as crystalline qualities of a 2-μm-thick InN film grown by molecular beam epitaxy (MBE) are characterized by Rutherford backscattering/channeling (RBS/C) and synchrotron radiation x-ray diffraction (SR-XRD).The minimum yield xmin=2.5％ deduced from the RBS/C results indicates a fairly good crystalline quality.From the SR-XRD results,we obtain the values of the screw and edge densities to be ρscrew =7.0027 X 109 and ρedge =8.6115 × 109 cm-2,respectively.The tetragonal distortion of the sample is found to be -0.27 ％ by angular scans,which is close to the -0.28 ％ derived by SR-XRD.The value of ｜e(⊥)/e‖｜ =0.6742 implies that the InN layer is much stiffer along the a axis than that along the c axis,where e‖ is the parallel elastic strain,and e⊥ is the perpendicular elastic strain.Photoluminescence results reveal a main peak of 0.653eV with the linewidth of 60meV,additional shoulder band could be due to impurities and related defects.%Dislocation information and strain-related tetragonal distortion as well as crystalline qualities of a 2-μm-thick InN film grown by molecular beam epitaxy (MBE) are characterized by Rutherford backscattering/'channeling (RBS/C) and synchrotron radiation x-ray diffraction (SR-XRD). The minimum yield Xmin=2.5% deduced from the RBS/C results indicates a fairly good crystalline quality. From the SR-XRD results, we obtain the values of the screw and edge densities to be pscrew = 7.0027 ×109 and pedge = 8.6115 ×109 cm-2, respectively. The tetragonal distortion of the sample is found to be-0.27% by angular scans, which is close to the -0.28 % derived by SR-XRD. The value of |e⊥/e|| | = 0.6742 implies that the InN layer is much stiffer along the a axis than that along the c axis, where e|| is the parallel elastic strain, and e⊥ is the perpendicular elastic strain. Photoluminescence results reveal a main peak of 0.653eV with the linewidth of 60meV, additional shoulder band could be due to impurities and related defects.