HANS LUDWIG HARTNAGEL is Professor at Darmstadt University of Technology in Darmstadt, Germany. RAMUNAS KATILIUS, PhD, is Professor and principal research associate of the Fluctuation Research Laboratory at the Semiconductor Physics Institute in Vilnius, Lithuania. ARVYDAS MATULIONIS, PhD, is Professor and Head of the Fluctuation Research Laboratory at the Semiconductor Physics Institute in Vilnius, Lithuania.