Time-resolved optical studies of silicon during nanosecond pulsed-laser irradiation

Journal Article · Wed Dec 15 04:00:00 EST 1982 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.26.6747· OSTI ID:6435588

Lowndes, D H; Jellison, Jr, G E; Wood, R F

The time-resolved optical transmission (at 1152-nm wavelength) and reflectivity (at both 633 and 1152 nm) of crystalline silicon have been measured with approx.nanosecond resolution during and immediately after pulsed-ruby-laser irradiation (694 nm, full width at half maximum pulse duration 14 nsec), over a range of pulsed-laser energy densities E/sub l/. For E/sub l/> or =0.8 J/cm/sup 2/ the transmission is found to go to zero and to remain at zero for a time proportional to E/sub l/ (during which time the reflectivity is also at a maximum value), and then to recover (in approx.500 nsec) to its initial value. The zero-transmission result during the high-reflectivity phase contradicts reports of other similar experiments. Measured reflectivities during the high-reflectivity phase agree with reflectivities calculated from the known optical constants of molten silicon, at both the 633- and 1152-nm probe wavelengths. Intense near-band-gap photoluminescence is also observed from our silicon samples, for E/sub l/ both above and below the threshold for the high-reflectivity phase. The results of detailed calculations using the thermal-melting model are presented. Good quantitative agreement is found between the results of these calculations and the measured melting threshold of 0.8 J/cm/sup 2/, and with the reflectivity and transmission of crystalline silicon, as functions of time and E/sub l/. The small (< or approx. =10%) absorption due to long-lived laser-induced free carriers is also calculated and found to be in satisfactory agreement with the measured transmission for long (> or approx. =100 nsec) times after pulsed-laser irradiation. The results are discussed in relation to other recent time-resolved measurements during pulsed-laser irradiation of silicon.

• Research Organization: Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• OSTI ID: 6435588
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 26:12; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY GAP
IRRADIATION
LASER RADIATION
LIGHT TRANSMISSION
LUMINESCENCE
MELTING
OPTICAL PROPERTIES
PHASE TRANSFORMATIONS
PHOTOLUMINESCENCE
PHYSICAL PROPERTIES
PULSES
RADIATIONS
RECRYSTALLIZATION
REFLECTIVITY
RESOLUTION
SEMIMETALS
SILICON
SURFACE PROPERTIES
TIME RESOLUTION
TIMING PROPERTIES