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Nanoscale Imaging of Buried Structures via Scanning Near-Field Ultrasound Holography G. S. Shekhawat and V. P. Dravid , Science , 310, 89(2005). Journal Club Presentation 30/10/06 Onur Basarir. Background AFM (Atomic Force Microscopy). AFM.
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Nanoscale Imaging of Buried Structures via Scanning Near-Field Ultrasound Holography G. S. Shekhawat and V. P. Dravid , Science, 310, 89(2005). Journal Club Presentation 30/10/06 Onur Basarir
AFM Superb spatial resolution, but nothing about subsurface properties.
Motivation • Near field SPM • Excellent lateral resolution • Ultrasound Non-destructive and depth sensitive • Holography Sensitive to phase
1 - Ultrasonic Force Microscopy O. Kolosov et.al, PRL, 81, 1046 (1998) F. Dinelli,et.al, PRB, 61,13995(2000).
2 – Acoustic Force Microscopy U. Rabe et.al. ,Ultrasonics, 38, 430(2000).
3 – Heterodyne Force Microscopy M T Cuberes et al 2000 J. Phys. D: Appl. Phys.33 2347-2355
Drawbacks of these Techniques • Contact mode • Amplitude measurements
Lock-in f2 f2-f1 f1 Setup for non-contact operation
Results I Nanostructures 500 nm below the surface
Conclusion • Non-invasive: based on acoustic waves • Sub-surface: transparent to acoustic waves • Nano-scale resolution