Investigation of materials of different crystal structure under various time delays using double pulse laser induced breakdown spectroscopy

Chemical etching method assisted double-pulse LIBS for the analysis of silicon crystals

“…Table 1 shows that the intensities of Si (100) lines are higher than those obtained in Ref. [39], where our result yields a strong dependence of the plasma emission intensities on the crystal orientation of the laser-irradiated solid sample. Furthermore, the experimental condition in our work is different from Ref.…”

“…Furthermore, the experimental condition in our work is different from Ref. [39] where two Nd:YAG lasers of 532 and 1064 nm wavelengths were combined in a crossedbeam double-pulse configuration (10 9 W/cm 2 , irradiance); in our work, two lasers of 266 and 1064 nm wavelengths with collinear configuration were focused at 45°incident angle in the double-pulse configuration (0.5 9 10 10 to 2.5 9 10 10 W cm -2 , irradiance). In addition, in Ref.…”

“…The missing bonds are defined as dangling bonds [38]. Si (100) samples have two bonded atoms leaving two dangling bonds [38,39]. Therefore, the ratio of dangling bonds is (100):(111) = 2:1.…”

“…While three of four coordination numbers of Si (111) surface are bonded, this leaves one dangling bond. Yurdanur-Tasel et al [39] calculated the dangling-bond density ratios as (100):(111) = 1:0.577 by using the planar density ratios. Banerjee explained that the Si (100) surface having two dangling bonds is ''highly reactive and unstable.''…”

“…Hence, the interaction within the laser spot changes from surface to surface, and this change can affect the relative emission intensity. The unstable and more active surface is leading to enhance the intensity of emission Si lines and to increase the growth of Si (100) planes faster than those in Si (111) [38,39]. Therefore, the intensity of emission lines of Si (100) surface is higher than those of Si (111) surface which may be due to the difference in dangling-bond densities.…”