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

Abstract

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 0to1000K. The pyroelectric coefficient is proportional to T3 at low temperature and increases acutely from 0 to around 400K, and then increases gently from 400to1000K. It makes AlN uniquely suitable for application in high temperature pyroelectric sensors. The spontaneous polarization of AlN changes a little from 0to1000K, which indicates that the features of III-nitrides based devices will hardly be degraded by the change of the spontaneous polarization.

The Influence of AlGaN Barrier-Layer Thickness on the GaN HEMT Parameters for Space Applications

“…In the area at the age of the gate stock, the field intensity can reach many megavolts per centimeter. However, this inevitably leads to the appearance inverse piezoelectric effect in the thin barrier layer that can cause significant mechanical stresses at the surface and in the bulk structure [4,24]. The appearance of the inverse piezoelectric effect is especially dangerous in a strong electric field.…”

Comparative study of AlN dielectric films’ electrical properties for MEMS capacitive switches

“…Moreover, these films possess a spontaneous polarization, associated to the wurtzite lattice structure, that is quite large and it can reach values up to 0.1 C/m 2 [1]. However this spontaneous polarization has been found to change a little with temperature and the pyroelectric effect plays a rather minor role to dielectric charging in these films [2,3].…”

Spontaneous polarization field in polar and nonpolar GaInN/GaN quantum well structures

“…As in other materials with spontaneous polarization, the bulk spontaneous polarization is neutralized by ions or other charged particles picked up from the air [3] and can only be observed by its temperature dependence known as pyroelectric effect. This has been studied by Bykhovski et al [4] for GaN and by Yan et al [5] for AlN. Up to now, the nature of the neutralizing particles on the surface is still unclear.…”