Raman Imaging and Raman Mapping - Emerging Raman Applications and Techniques in Biomedical and Pharmaceutical Fields - page 99

Fig. 5.1. a and b 4 . 0 × 1 . 3 μm 2 near-field reflectance and confocal Raman im-
ages of periodic poly-Si lines on a patterned SiGe wafer with buried SiGe stressors
obtained in about 6 min, respectively, generated from the Si-Si peak intensity. c
Three-dimensional near-field Raman image from Si-Si peak position showing the
spatial variation of relative strain in a selected region of the wafer (reprinted with
permission from [20]. Copyright 2008 Optical Society of America)
gold is injected into the cell. However, electrodes deposited on the end of an
optical fiber or metallic tip can also be used. If an AFM tip coated with gold
or silver is used for scanning, the technique is usually called tip-enhanced
Raman spectroscopy (TERS) [24]. TERS imaging is extraordinarily sensitive,
but tip fabrication and operation remain dicult.