Modified triglycine sulphate for pyroelectric infrared detectors

Abstract

Doped single crystals of the TGS family show very good pyroelectric and dielectric properties, which enable them to be applied in pyroelectric detectors. Single domain deuterated and 1-α-alanine doped TGS crystals (DTGS:L-A) and TGS crystals doped with a l-α-alanine/Cr³⁺ complex (TGS:L-A + Cr³⁺) were grown. By deuteration Curie temperature can be increased up to 61°C. To improve homogeneity of alanine incorporation and so the uniformity of the internal bias field, the DTGS:L-A crystals were grown at {001} plate seeds¹⁰ by the so called box method. TGS:L-A + Cr³⁺ have extremely high bias fields of more than 50 kV/cm. Thus a high pyroelectric effect is measured even at 100°C. As a result of extensive investigations low dielectric losses of about 2^. 10^-4… 1^.10^-3 at a frequency of 10³ cps could be achieved with the doped modifications. Finally, the pyroelectric chips of single element, linear and two-dimensional arrays were described and the measured detector properties were summarised.

Key Words:

• triglycine sulphate
• pyro- and dielectric properties
• pyroelectric detector