2.4. Vacuum System
Vacuum system consists of a vacuum chamber that made of a stainless steel with an inner diameter of 20 cm and
a height of 20 cm. One window on the sidewall of the vacuum chamber was mounted with a ZnSe lens to transmit
the CO2 laser radiation into the vacuum chamber. The transmitted laser radiation was then focused onto the
surface of TE target. The vacuum system consists of a mechanical rotary pump (Balzers, DUO 1.5 A) and diffusion
pump (Balzers, DIF040L). The pressure in the vacuum chamber was measured by Pirani gauge and Penning
gauge.
2.5. Characterization
Before and after the laser ablations, the mass of TE target was measured using a digital balance with an accuracy
of ±0.1 mg (A & D, GR series). Then, the mass lost of TE target was obtained. The ablated area and penetration
depth on the TE target surface was observed by an optical microscope. The cross-section and surface morphologies
of the TE films were investigated using field emission scanning electron microscopy (FE-SEM: Hitachi,
S-4700). The crystalline structure of the TE films was investigated by X-ray diffraction (XRD: Rigagu, Rint
2000) using CuKα radiation operated at 40 kV and 40 mA. The XRD patterns were recorded at grazing incidence
angle of 3˚ in the 2θ range of 20˚ to 60˚ with a scanning rate of 2˚/min.
3. Results and Discussion
Figure 3 shows the surfaces of TE target after ablating for 1, 2 and 3 h. The mass of TE target was measured
before and after laser ablations. Therefore, the mass lost of the target was obtained and listed in Table 1.