| 摘要 |
<p>Compositional modifications are provided for the ferroelectric material lead scandium tantalate (PST), which improve its performance as an electronic material. PST is of particular use in infrared detection applications, in the form of the sensitive material of a dielectric bolometer, but its optimum performance occurs at about 50 DEG C. The compositional modifications described enable this optimum temperature to be adjusted, to match a particular application, without loss of peak sensitivity. One modification provides the substitution of a bismuth/potassium mixture for a proportion of the lead to lower this optimum temperature. for example, to achieve the best performance at typical ambient conditions, near 20 DEG C. A second modification increases this temperature by substituting niobium for a proportion of the tantalum. This allows detector operation over a wide range of external temperatures with stabilisation by heating, but without any requirement for cooling. Both compositional modifications provide for a valence balance between substituting and substituted elements. This ensures that the electrical resistivity of the material is not lowered significantly by either modification. This is of particular importance for low noise, dielectric bolometer detectors. The material may be prepared by hot pressing/sintering methods or by thin layer deposition methods.</p> |
