Pyroelectricity in gallium nitride thin films

We report on the measurements of the pyroeffect in wurtzite if-type GaN films deposited over basal plane sapphire substrates. We measured the voltage drop between the contacts while the sample was subjected to the uniform heating or cooling. The pyroelectric voltage coefficient extracted from our data is comparable to that of the pyroelectric ceramics (similar to 10(4) V/m K). Our results show that the pyroelectric effect in GaN is a combination of a fast response to an initial heat flow and a slower response related to a change in the sample temperature. (C) 1996 American Institute of Physics.