Studying the Pyroelectric Effect in AlN Epilayers

We have studied the pyroelectric effect in 6- to 12-μm-thick AlN epilayers grown by hydride–chloride vapor phase epitaxy (HVPE) on 4H-SiC substrates. The pyroelectric current was generated by means of dynamic laser action. Evolution of the temperature fields was monitored by direct measurements of the surface temperature with allowance for the specific thermal heterogeneity of the AlN/SiC system. In combination with the results of pyroelectric current measurements, these data allowed the pyrocoefficient of the AlN/SiC structure to be estimated at p ≈ 3.0 μC/(m² K). Pyroelectric figures of merit of the given structure are calculated that can be used for the comparison of pyroelectric materials intended for the creation of IR radiation detectors.