By Topic

Time-resolved picosecond infrared absorption induced by high-density photogenerated carriers in Ge and CdSe

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

4 Author(s)
N. Ockman ; Department of physics and the institute for ultrafast spectroscopy and lasers, city college of New York, NY., USA ; R. Dorsinville ; Wubao Wang ; R. Alfano

Picosecond time-resolved absorption at 2.2, 3.4, and 3.9 μm produced by photogenerated carriers in intrinsic Ge and semi-insulating CdSe has been measured at room temperature. For Ge, the peak absorbance changes as the square of the probe wavelength. The absorption profile as a function of delay time relative to the excitation pulse rises with a resolution-limited risetime (< 10 ps) and decays over the range from several hundred picoseconds to several nanoseconds. These observations can be accounted for by free-carrier absorption and Auger recombination. Intervalence transitions make a small contribution (∼ 17 percent) to the induced absorption only at 2.2 μm. For CdSe, the absorption change with time exhibits a more complex profile. Two temporal peaks occur for probing wavelengths at 3.4 and 3.9 μm and three peaks occur at 2.2 μm. The first peak occurring at about 5 ps after excitation for all three probe wavelengths with a resolution-limited risetime is due to free-carrier absorption. The other peaks have been attributed to transitions involving impurity (defect) levels by trapped photogenerated carriers.

Published in:

IEEE Journal of Quantum Electronics  (Volume:23 ,  Issue: 11 )