Temperature dependence of the pyroelectric coefficient and the spontaneous polarization of AlN

Using the Debye model and existing experimental data of the pyroelectric coefficient of AlN, the temperature dependence of the pyroelectric coefficient as well as the spontaneous polarization of AlN is calculated over a wide temperature range from 0 to 1000 K. The pyroelectric coefficient is proportional to T-3 at low temperature and increases acutely from 0 to around 400 K, and then increases gently from 400 to 1000 K. It makes AlN uniquely suitable for application in high temperature pyroelectric sensors. The spontaneous polarization of AlN changes a little from 0 to 1000 K, which indicates that the features of III-nitrides based devices will hardly be degraded by the change of the spontaneous polarization. (c) 2007 American Institute of Physics.