Dislocation luminescence in GaN single crystals under nanoindentation
نویسندگان
چکیده
This work presents an experimental study on the dislocation luminescence in GaN by nanoindentation, cathodoluminescence, and Raman. The dislocation luminescence peaking at 3.12 eV exhibits a series of special properties in the cathodoluminescence measurements, and it completely disappears after annealing at 500°C. Raman spectroscopy shows evidence for existence of vacancies in the indented region. A comprehensive investigation encompassing cathodoluminescence, Raman, and annealing experiments allow the assignment of dislocation luminescence to conduction-band-acceptor transition involving Ga vacancies. The nanoscale plasticity of GaN can be better understood by considering the dislocation luminescence mechanism.
منابع مشابه
Luminescence properties of mechanically nanoindented ZnSe
In this study, we used cathodoluminescence (CL) spectroscopy to examine the CL emissions of zinc selenide (ZnSe) single crystals that had been subjected to Berkovich nanoindentation. The CL spectra of the ZnSe exhibited both impurity emission peaks (1.8–2.4 eV band) and near-bandgap emission peaks (2.68 eV). Although CL emissions were generated during four unloading/reloading cycles, the decrea...
متن کاملAn Energy Balance Criterion for Nanoindentation-Induced Single and Multiple Dislocation Events
Small volume deformation can produce two types of plastic instability events. The first involves dislocation nucleation as a dislocation by dislocation event and occurs in nanoparticles or bulk single crystals deformed by atomic force microscopy or small nanoindenter forces. For the second instability event, this involves larger scale nanocontacts into single crystals or their films wherein mul...
متن کاملSimulating nanoindentation and predicting dislocation nucleation using interatomic potential finite element method
Dislocation nucleation is central to our understanding of the onset of plasticity during nanoindentation. The shear stress in small volumes beneath the nanoindenter can achieve the theoretical limit of a perfect crystal. The ensuing nonlinear elastic instability can trigger homogenous dislocation nucleation inside the crystal. Here we employ the interatomic potential finite element method to si...
متن کاملDislocation nucleation in bcc Ta single crystals studied by nanoindentation
The study of dislocation nucleation in close-packed metals by nanoindentation has recently attracted much interest. Here, we address the peculiarities of the incipient plasticity in body centered cubic bcc metals using low index Ta single crystals as a model system. The combination of nanoindentation with high-resolution atomic force microscopy provides us with experimental atomic-scale informa...
متن کاملMechanical Deformation Behavior of Nonpolar GaN Thick Films by Berkovich Nanoindentation
In this study, the deformation mechanisms of nonpolar GaN thick films grown on m-sapphire by hydride vapor phase epitaxy (HVPE) are investigated using nanoindentation with a Berkovich indenter, cathodoluminescence (CL), and Raman microscopy. Results show that nonpolar GaN is more susceptible to plastic deformation and has lower hardness than c-plane GaN. After indentation, lateral cracks emerge...
متن کامل