The Effect of Thickness and Doping on the Nonlinear Absorption Behaviour of IIIA-VIA Group Amorphous Semiconductor Thin Films

2011-06-30
Kurum, Ulas
YAĞLIOĞLU, HALİME GÜL
YÜKSEK, MUSTAFA
ELMALI, Ayhan
Ates, Aytunc
KARABULUT, MEVLÜT
Mamedov, Gasan M.
Hasanlı, Nızamı
The nonlinear optical absorption of InSe, GaSe and GaxIn1-xSe amorphous films with varying thickness and doping has been studied by open-aperture Z-scan experiment with 4 ns and 65 ps pulse durations at 1064 nm wavelength and femtosecond pump-probe spectroscopy. Our results show that the dopant and film thickness (from 20 nm to 104 nm) results in switching from saturable absorption to nonlinear absorption for equal input intensities. This behaviour is attributed to increasing localized defect states with increasing film thickness and/or dopant. The experimental curves were fitted to the theory of open aperture Gaussian beam Z-scan based on the Adomian decomposition method incorporating one photon, two photon, and free carrier absorptions and their saturations. By preparing very thin amorphous thin films the saturation threshold has been lowered significantly.

Suggestions

The role of defects on the transition from saturable absorption to nonlinear absorption of Bi12GeO20 single crystal under increasing laser excitation
PEPE, YASEMİN; Isik, Mehmet; KARATAY, AHMET; YILDIZ, ELİF; Hasanlı, Nızamı; ELMALI, AYHAN (2022-11-01)
© 2022 Elsevier B.V.This work reports defect and input intensity dependent nonlinear optical behaviors of Bi12GeO20 (BGO) single crystal. Open aperture (OA) Z-scan experiments were performed with 532 nm excitation wavelength under 4 ns and 100 fs pulsed laser irradiation. Obtained data were fitted with a theoretical model considering one-photon, two-photon and free carrier absorption contributions to nonlinear absorption due to longer lifetime of localized defect states than that of used laser pulse duratio...
The flow of excitation energy in LHCII monomers: Implications for the structural model of the major plant antenna
Gradinaru, CC; Ozdemir, S; Gulen, D; van Stokkum, IHM; van Grondelle, R; van Amerongen, H (1998-12-01)
Spectral and kinetic information on energy transfer within the light-harvesting complex II (LHCII) monomer was obtained from this subpicosecond transient absorption study, by using selective excitation (663, 669, 672, 678, and 682 nm) of various Chl a absorption bands and detecting the induced changes over the entire Q(y) region (650 -700 nm). It is shown that transfer from the pigment(s) absorbing around 663 nm to the low energy ones occurs in 5 +/- 1 ps, whereas the 670-nm excitation is delivered to the s...
Structural and optical properties of thermally evaporated Cu-Ga-S (CGS) thin films
Gullu, H. H.; IŞIK, MEHMET; Hasanlı, Nızamı (2018-10-15)
The structural and optical properties of thermally evaporated Cu-Ga-S (CGS) thin films were investigated by Xray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM) and optical transmittance measurements. The effect of annealing temperature on the results of applied techniques was also studied in the present paper. EDS results revealed that each of the elements, Cu, Ga and S are presented in the films and Cu and Ga concentration increases whereas S concentration decr...
Experimental investigation of waveform tip injection on the characteristics of the tip vortex
Ostovan, Yashar; Uzol, Oğuz; Department of Aerospace Engineering (2011)
This study investigates the effect of chordwisely modulated tip injection on the flow and turbulence characteristics of the tip vortex through experimental measurements downstream of a rectangular half-wing that has an aspect ratio of three. This injection technique involves spanwise jets at the tip that are issued from a series of holes along the chord line normal to the freestream flow direction. The injection mass flow rate from each hole is individually controlled using computer driven solenoid valves a...
Observation of coherent nonlinear interactions in the ion velocity distribution function
Uzun Kaymak, İlker Ümit (2006-11-01)
Using laser induced fluorescence (LIF) and higher order spectral analysis, we present the first measurements of phase space resolved coherent nonlinear interactions among the components of low frequency density fluctuations, (omega <=omega(ci)), in a linearly magnetized device. The bicoherence calculations employing the two point correlation technique suggest that there are two different coherent nonlinear wave-wave interactions in the measured spectrum. The first one, having a short correlation length and ...
Citation Formats
U. Kurum et al., “The Effect of Thickness and Doping on the Nonlinear Absorption Behaviour of IIIA-VIA Group Amorphous Semiconductor Thin Films,” 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/53603.