Effects of growing conditions on preparation of InSb thin films by femtosecond pulsed laser deposition

A series of InSb thin films were fabricated on the sapphire substrate by femtosecond pulsed laser deposition (fsPLD) method with the laser of 110 fs pulse width. The laser incident energy is near 1mJ. The target is one kind of heavily doped n-type InSb. The substrate temperature changes from 80 oC to 400 oC, Laser frequency changes from 1 Hz to 1 kHz and laser energy density changes from 0.1 J/cm 2 to 1 J/cm 2 . The effects of different laser frequencies, substrate temperature and laser energy density on the surface morphology and optical property have been investigated separately. The surface morphology of InSb thin films was observed by metallurgical microscope and scanning electron microscope (SEM). The thin film with better surface morphology is obtained when the laser frequency is 10 Hz, substrate temperature is 80 oC and laser energy density is 0.1 J/cm 2 . X-ray diffraction (XRD) demonstrates that the InSb thin film has a good single crystal structure. The infrared transmittance of InSb thin films is measured by an infrared spectrometer. The results show that good InSb thin films can be prepared by fsPLD. It is found that the mid-wavelength Infrared transmission through the InSb thin films is near 55% and it almost does not change under the different growing conditions.