Sample #

Beam type

with Al

after Al removal

f0 (Hz)

Q

f0 (Hz)

Q

1

Si/Porous Si

5198.4

1529

2

Si

5471.6

2880

5464.1

3214

3

Si

5567.2

2930

4

Si

5501.6

3236

5

Si

5334.6

2540

6

Si

5366.4

3157

7

Si

5442.3

2474

5434.4

2860

Mean value

Si

≈5447

≈2870