1.1 Piezoelectric semiconductors and ceramics
Among semiconductor crystals, a family of wurtzite – type belongs to the 6mm class, which is piezoelectric active. The material properties (Tsai, 1992) and the norm calculations are in Table 1. From the table, the most piezoelectric effective among the five materials is CdS which has a very important feature in the thin films of semiconductors. For piezoelectric ceramics, the most potential piezoelectric material because of its higher strength, high rigidity and more importantly the better piezoelectricity, Table 2 includes the piezoelectric coefficients (Temple, 1960) and calculated norms. From the table, the most effective piezoelectric among the seven ceramics is PZT-5H.
|
Material |
d11 |
d33 |
d15 |
N |
|
BeO |
-0.12 |
0.24 |
0.29 |
|
|
ZnO |
-5.0 |
12.4 |
-8.3 |
18.48 |
|
CdS |
-5.2 |
10.3 |
-14.0 |
23.50 |
|
CdSe |
-3.9 |
7.8 |
-10.0 |
17.07 |
|
Table 1. The Constants and Norms of Piezoelectric Semiconductors[10-12 C N-1] |
|
Material |
d11 |
d33 |
d15 |
N |
|
PZT-4 |
-5.2 |
15.1 |
12.7 |
24.59 |
|
PZT-5 |
-5.4 |
15.8 |
12.3 |
24.71 |
|
BaTi O3 |
-4.35 |
17.5 |
11.4 |
18.82 |
|
PZT-5H |
-6.5 |
23.3 |
17 |
34.72 |
|
PZT-6B |
-0.9 |
7.1 |
4.6 |
9.71 |
|
PZT-8 |
-4.0 |
23.3 |
10.4 |
28.13 |
|
C-24 |
1.51 |
8.53 |
3.89 |
10.37 |
|
Table 2. The Constants and Norms of Piezoelectric Ceramics [10-12 C N-1] |
