Praveena Manimunda, Francis Ndi, Horiba Instruments Inc., Piscataway, NJ
Wide bandgap semiconductors such as silicon carbide and Ga₂O₃, are used in power electronics, high power and high temperature devices. Achieving defect free, doped wide bandgap semiconductors are still a challenge. In this study, spectroscopic characterization techniques such as photoluminescence, Raman and cathodoluminescence methods are utilized to identify microscopic defects in doped n-type 4H-SiC and shape engineered SnO₂ nanostructures grown on Ga₂O₃ nanowires. Semiconducting oxide nanostructures are developing as a feasible candidate for applications such as mechanical and optical resonators. However, attaining efficiently doped oxide nanowires with manageable conductivity is still a challenge. Creating semiconducting oxide nanostructures needs extensive understanding of their morphology and wants efficient multimodal characterization systems. Multimodal spectroscopy is the concept of merging several spectroscopic techniques onto one platform, thereby expanding the extent of analytical capabilities available on that single platform. Besides the apparent benefit of cost reduction, having multiple analytical spectroscopies offers the added benefit of sample colocalization so that multiple paired measurements can be made at the same location of the sample. The advantage of colocalization is particularly crucial as feature sizes get smaller, from a few microns to nanometers in size. Using patterned silicon grid sample and embedded position-sensing technology, coordinates of region of interest transferred between different spectroscopic tools. Panchromatic CL images identified the region of illumination on connected nanowires while Raman mapping identified chemical composition variations. SEM micrographs identified regions of SnO₂ on Ga₂O₃. These regions showed stronger emission ~ 1.94 eV. The orange band was attributed to the oxygen vacancies in SnO₂. The study also discusses the application of combined photoluminescence and Raman spectroscopy in detecting growth induced defects in 4H SiC samples.