Abstract
Mechanisms for optical nonlinearities and ultrafast carrier dynamics in CuxS 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 CuxS NC's formed by direct- and indirect-gap phases of copper sulfide is confirmed by results of the Z-scan measurements.
| Original language | English |
|---|---|
| Pages (from-to) | 8087-8094 |
| Number of pages | 8 |
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 54 |
| Issue number | 11 |
| Publication status | Published - Sep 15 1996 |
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ASJC Scopus subject areas
- Condensed Matter Physics
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Mechanisms for optical nonlinearities and ultrafast carrier dynamics in CuxS nanocrystals. / Klimov, Victor I; Karavanskii, Vladimir A.
In: Physical Review B - Condensed Matter and Materials Physics, Vol. 54, No. 11, 15.09.1996, p. 8087-8094.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mechanisms for optical nonlinearities and ultrafast carrier dynamics in CuxS nanocrystals
AU - Klimov, Victor I
AU - Karavanskii, Vladimir A.
PY - 1996/9/15
Y1 - 1996/9/15
N2 - Mechanisms for optical nonlinearities and ultrafast carrier dynamics in CuxS 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 CuxS 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 CuxS 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 CuxS 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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M3 - Article
VL - 54
SP - 8087
EP - 8094
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 11
ER -