Nanosecond and Femtosecond UV Laser Ablation of CdTe (100): Time-Of-Flight and Angular Distributions

Abstract

AbstractAngularly resolved time-of-flight (TOF) measurements have been used to probe the velocity and angular distributions of Cd atoms and Te2 molecules ejected from CdTe (100) substrates under irradiation by 248 nm nanosecond and sub-picosecond laser pulses. These experiments employ a dye laser TOF mass spectrometer with resonance enhanced multiphoton ionization for sensitive, high resolution detection of the desorbed products. The velocity distributions are well described by Maxwell-Boltzmann distributions for low fluence nanosecond (<60 mJ/cm2) and sub-picosecond (<3.3 mJ/cm2) pulses. Angular flux distributions for nanosecond irradiation are observed to be highly forward peaked about the surface normal, whereas, for sub-picosecond irradiation the distribution approaches cos3θ.