Introduction

The natural world is filled with rough surfaces. Roughness is, however, a relative term. One may describe a sheet of paper as being smooth to the touch, whereas on an atomic scale one would observe deep valleys and tall mountains in the landscape. Of particular scientific interest in the past few decades have been surfaces that exhibit this rough behavior on a nanometer scale, often referred to as thin film surfaces. Numerous studies have been carried out investigating processes to create thin films, characterize them, and test their physical properties [187]. The physics behind the growth and structure of these surfaces has been shown to be very interesting and challenging due to the complexities of the growth processes and surface structures [8, 40, 104, 112]. Specifically, surface and interface roughness controls many important physical and chemical properties of films. For example, the electrical conductivity of thin metal films depends very much on surface and interface roughness [135], and the reliability of a Si MOSFET (metal-oxide-semiconductor fieldeffect transistor)channel depends on the roughness of the gate oxide—silicon interface [82]. Also, interface roughness has a profound effect on the magnetic hysteresis of a magnetic film [115], and controls optical losses in optical waveguides [130]. Rough surfaces can increase the effective area for advanced charge storage devices [19], as well as promote capillary forces through wicking in modern heat pipe design [51]. These properties of thin films are exploited in a number of applications, including semiconductor devices [153], solar cells [127 ], and thin-film transistor (TFT) displays [73].