Temperature effect on (2+1) experimental Kardar-Parisi-Zhang growth

TL;DR

This study investigates how substrate temperature influences the growth dynamics of polycrystalline CdTe thin films, revealing temperature-dependent transitions in growth behavior and demonstrating control over KPZ non-linearity.

Contribution

It shows that substrate temperature affects growth regimes and allows tuning of KPZ non-linearity in thin film deposition, confirmed by experimental data and Monte Carlo simulations.

Findings

Temperature-dependent mound evolution observed.

Growth transitions from uncorrelated to correlated regimes.

CdTe growth follows KPZ universality class across temperatures.

Abstract

We report on the effect of substrate temperature (T) on both local structure and long-wavelength fluctuations of polycrystalline CdTe thin films deposited on Si(001). A strong T-dependent mound evolution is observed and explained in terms of the energy barrier to inter-grain diffusion at grain boundaries, as corroborated by Monte Carlo simulations. This leads to transitions from uncorrelated growth to a crossover from random-to-correlated growth and transient anomalous scaling as T increases. Due to these finite-time effects, we were not able to determine the universality class of the system through the critical exponents. Nevertheless, we demonstrate that this can be circumvented by analyzing height, roughness and maximal height distributions, which allow us to prove that CdTe grows asymptotically according to the Kardar-Parisi-Zhang (KPZ) equation in a broad range of T. More important, one finds positive (negative) velocity excess in the growth at low (high) T, indicating that it is possible to control the KPZ non-linearity by adjusting the temperature.