TY - JOUR
T1 - Mechanisms for optical nonlinearities and ultrafast carrier dynamics inS nanocrystals
AU - Klimov, Victor I.
AU - Karavanskii, Vladimir A.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1996
Y1 - 1996
N2 - Mechanisms for optical nonlinearities and ultrafast carrier dynamics in (Formula presented)S nanocrystals (NC’s) are studied using femtosecond pump-probe techniques and nanosecond Z-scan measurements. Depending on the copper deficiency, transient absorption is dominated either by state-filling-induced bleaching [for copper sulfide phases with x = 1.8 (digenite), 1.9, and 1.96 (djurleite)] or by photoinduced absorption [x = 2 (chalcosite)]. This difference is explained in terms of the change in the dominant nonlinear-optical mechanism resulting from an indirect-direct-gap transformation accompanying the increase in copper deficiency. Extremely fast signal relaxation (on the time scale from 400 fs to 4 ps) observed in the initial stage after excitation is attributed to carrier trapping. The existence of different types of nonlinearities in (Formula presented)S NC’s formed by direct- and indirect-gap phases of copper sulfide is confirmed by results of the Z-scan measurements.
AB - Mechanisms for optical nonlinearities and ultrafast carrier dynamics in (Formula presented)S nanocrystals (NC’s) are studied using femtosecond pump-probe techniques and nanosecond Z-scan measurements. Depending on the copper deficiency, transient absorption is dominated either by state-filling-induced bleaching [for copper sulfide phases with x = 1.8 (digenite), 1.9, and 1.96 (djurleite)] or by photoinduced absorption [x = 2 (chalcosite)]. This difference is explained in terms of the change in the dominant nonlinear-optical mechanism resulting from an indirect-direct-gap transformation accompanying the increase in copper deficiency. Extremely fast signal relaxation (on the time scale from 400 fs to 4 ps) observed in the initial stage after excitation is attributed to carrier trapping. The existence of different types of nonlinearities in (Formula presented)S NC’s formed by direct- and indirect-gap phases of copper sulfide is confirmed by results of the Z-scan measurements.
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U2 - 10.1103/PhysRevB.54.8087
DO - 10.1103/PhysRevB.54.8087
M3 - Article
AN - SCOPUS:0000124502
VL - 54
SP - 8087
EP - 8094
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 11
ER -