Rida Ahmed, MS Physics, 2016-2018 Supervised by Dr. Naveed Ahmad
Investigation of mechanical, electrical and morphological properties of laser-irradiated lead substrate
/ Rida Ahmed
- Lahore : Divison of Science & Technology, Univeristy of Education, 2018
- xiii, 49 p. CD
The effect of ambient environment and laser fluence has been investigated on the sputtering yield as well as surface modifications of Lead (Pb). Lead targets were exposed to Nd:YAG laser (532 nm, 6 ns) at various fluences ranging from 6.4 J cm-2 to 15.4 Jcm-2. Quartz Crystal Microbalance (QCM) was employed as a tool for sputtering yield measurement of Pb under inert and reactive environment of (Ar and O2) at pressure of 200 torr. It is revealed that sputtering yield of Pb varies from 3.6 × 1013 to 13.1 × 1013 atoms/pulse is strongly dependent upon fluence and environmental conditions. The sputtering yield increases non-monotonically with increasing the laser fluence and its value is higher in case of Argon. The analysis of profilometry of ablated crater on lead surface explored by optical microscopy is well correlated with QCM measurements. The surface modifications of laser bombarded lead are investigated using Scanning Electron Microscopy (SEM). Its analysis reveals the growth of globules, droplets, and conical structures. The crater diameter as well as growth of surface structures are dependent upon the laser fluence. The X-ray diffraction (XRD) confirms that no new phases are formed. The micro hardness explored by Vickers micro hardness shows an increasing trend with increasing fluence. The higher sputtering yield of Pb in Ar as compare to O2 is observed. Surface modifications of Pb explained by SEM analysis are correlated with sputtering yield measurement. The other characterization techniques employed for crater depth measurements, structural modifications, and mechanical properties are optical microscopy, XRD analysis, and micro hardness tester.