Effect of temperature on the Hurst and growth exponents of CdTe polycrystalline films

Abstract

We have studied the influence of substrate temperature on the Hurst and growth exponents of CdTe thin films grown on glass substrates covered by fluorine doped tin oxide. The sample roughness profile was measured with a stylus profiler at different growth times and substrate temperatures in order to determine the critical exponents. The Hurst exponent increases linearly from 0.72 to 0.8, whereas the growth exponent increases exponentially from 0.14 to 0.62, for temperatures between 150 and 300°C. The global roughness also increases with growth temperature, which turns to be a very good parameter for roughness control.

Faceted anomalous scaling in the epitaxial growth of semiconductor films

“…The real space scaling of this system was previously investigated [9,13]. In the present work, we identify a crossover in the dynamical scaling exponents not noticed in Ref.…”

“…The GDST foresees therefore faceted morphologies with local roughness exponent α loc = 1 that represents locally smooth surfaces. The height-height correlation function exhibits scaling only for l l c and the local roughness exponents are in the interval 0.7-0.8, indicating self-affine surfaces as described in a previous study of this system [9]. However, high resolution AFM images confirm that the surfaces are faceted.…”

“…Details of the growth system and sample preparation can be found elsewhere [9,15]. It is important to mention that the growth of some samples was repeated using the molecular beam epitaxy technique and they exhibited the same behaviour.…”

Sub-bandgap photoluminescence from as-grown and annealed layers of CdTe

“…Largely, the majority of known and potential applications rely on the CdTe layers, which are produced on various substrates. Silicon, GaAs, glass and sapphire are most often the substrates of choice as they are inexpensive and available in large wafer sizes [6][7][8][9][10]. Very often the physical parameters, which influence the efficiency of the photovoltaic devices, emitters and detectors, are determined by the defects in the CdTe and interface layers [11].…”

Detrending moving average algorithm: A closed-form approximation of the scaling law

“…Long-memory stochastic processes are ubiquitous in fields as different as condensed matter, biophysics, social science, climate change, finance [1,2,3,4]. The development of methods able to quantify the statistical properties and, in particular, to extract the Hurst exponent of long-range correlated signals continue therefore to draw the attention not only of the physicist community [5,6,7,8,9,10,11,12,13,14,15].…”