Anomalous scaling and super-roughness in the growth of CdTe polycrystalline films

Abstract

CdTe films grown on glass substrates covered by fluorine doped tin oxide by Hot Wall Epitaxy (HWE) were studied through the interface dynamical scaling theory. Direct measures of the dynamical exponent revealed an intrinsically anomalous scaling characterized by a global roughness exponent $\alpha$ distinct from the local one (the Hurst exponent $H$), previously reported [Ferreira \textit{et al}., Appl. Phys. Lett. \textbf{88}, 244103 (2006)]. A variety of scaling behaviors was obtained with varying substrate temperature. In particular, a transition from a intrinsically anomalous scaling regime with $H\ne\alpha<1$ at low temperatures to a super-rough regime with $H\ne\alpha>1$ at high temperatures was observed. The temperature is a growth parameter that controls both the interface roughness and dynamical scaling exponents. Nonlocal effects are pointed as the factors ruling the anomalous scaling behavior.