In this work, the problem of the thermal characterization of two-layer systems by means of the photoacoustic technique is discussed. For a two-layer system under rear-side illumination conditions, we have applied the Rosencwaig and Gersho model for calculating the pressure fluctuation in the photoacoustic gas chamber. The limiting cases in which both layers are thermally thin, thermally thick and one layer is thermally thin and the other is thermally thick are discussed. When both layers are thermally thin, a consistent equation for the heat capacity is obtained and an effective thermal diffusivity equation is derived when both layers are thermally thick. In order to test our theoretical results, we apply them to two-layer systems consisting of AlGaAs layers of different Al concentrations, grown by liquid phase epitaxy on GaAs substrates. The results of our measurements are in good agreement with the theoretical predictions. Our results show the general character of the expression for the effective thermal diffusivity of two-layer systems reported by Mansanares et al (1990 Phys. Rev. B 42 4477).

In this article the transport of modulated heat is studied in a system consisting of two layers with a thermal resistance between them. It is shown that in a photothermal experiment, the measurement of the temperature in the rear face can be used for the determination of the thermal resistance of the inner layer. The system consisting of two foils of aluminum joined by a glue of different thickness is studied using the open photoacoustic cell technique. Our approach shows that it can be used for the determination of the thermal resistance and thermal conductivity of the buried layer.

The two layer system AlyGa1−yAs on GaAs is studied in the range (0⩽y≲1). The open photoacoustic cell technique is used to obtain thermal diffusivity, thermal conductivity, heat capacity, and the thermal expansion coefficient. It is shown that the thermal properties of the individual layers can be determined using the low modulation frequency regime models without actually separating the two layer system. The possibilities and advantages of the approach for the thermal characterization of layered semiconductor systems are discussed.

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