1. Physics Department, German University in Cairo, Entrance El Tagamoa El Khames, New Cairo City 11835, Cairo, Egypt, Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Appelstrasse 9a, Leibniz University Hannover, 30167 Hannover, Germany, and Research Unit, Draegerwerk AG & Co. KGaA, D-23542 Luebeck, Germany