Anomalous Thermal Diffusivity of Amorphous Semiconductor Superlattices
Since the development of amorphous semiconductor superlattice films, the great interesting in fundamental and technological is attracted by their special properties and applications. The optical and electronic properties of the films have been studied by conventional spectroscope, photoluminescence and photoconductance techniques etc. Some anomalous phenomena, such as, the quantum size effect and the permenent photoconductivity (PPC) effect, have been discovered [1–2]. Recently the investigations of the characteristics and parameters of amorphous semiconductor superlattice films by photoacoustic and photothermal techniques are being got attention [3,4]. In this paper, we describe the study of the thermal diffusivity of a series samples of amorphous semiconductor superlattices a-Si:H/a-SiNx:H. The thermal diffusivity of the samples is experimentally measured by using mirage detection technique [5,6]. Up to date, the mirage detection method has been used successfully to determine the thermal diffusivity of both transparent and opaque materials. Specially it is available to measure directly the thermal parameters of thin films which are usually difficalt to be, evaluated. In the theoretical calculation, one dimensional model with “ the thormal resistors in series “ and ” the weighted average ” is used. Comparing the experimental and theoretical results, we find that both are in good agreement for the most of the samples. However, some anomalous thermal diffusivity phenomena have been observed in some special samples.
KeywordsThermal Diffusivity Relative Thickness Amorphous Semiconductor Thermal Effusivities Thermal Resistor
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