Surface Composition Changes and Ablation Dynamics in Excimer Laser Irradiated CdTe

1990 ◽  
Vol 191 ◽  
Author(s):  
P. D. Brewer ◽  
J. J. Zinck ◽  
G. L. Olson
Keyword(s):  
Laser Ablation ◽  
Excimer Laser ◽  
Surface Composition ◽  
Laser Ablation Process ◽  
Flight Mass Spectrometry ◽  
Rich Condition ◽  
Thermal Mechanism ◽  
Krf Excimer Laser ◽  
Composition Changes ◽  
Cdte Surface

ABSTRACTWe have investigated the dynamics of KrF excimer laser ablation of CdTe and the fluence dependent changes in surface stoichiometry that accompany the laser ablation process. The composition of the CdTe surface was reversibly controlled between stoichiometric and a Te-rich condition by varying the laser fluence over the range from 15–65 mJ/cm2. The primary species ejected from the irradiated surface were Cd atoms and Te2 molecules. Their velocity distributions as measured by time-of-flight mass spectrometry were found to be Maxwellian. From the analysis of the velocity distributions, the preferential desorption of surface atoms, and the reversible nature of the process, we conclude that the desorption is due to a photo-thermal mechanism which mediates the competition between Te2 formation and desorption and the desorption of Cd atoms.

Effects of Processing Parameters on KrF Excimer Laser Ablation Deposited ZrO2 Films

1991 ◽  
Vol 236 ◽  
Author(s):  
Gary A. Smith ◽  
Li-Chyong Chen ◽  
Mei-Chen Chuang
Keyword(s):  
Laser Ablation ◽  
Substrate Temperature ◽  
Excimer Laser ◽  
Deposition Rate ◽  
Oxygen Pressure ◽  
Pressure Dependence ◽  
Laser Fluence ◽  
X Ray ◽  
Excimer Laser Ablation ◽  
Krf Excimer Laser

AbstractSystematic experiments have been carried out to characterize the yttria containing zirconia thin films on sapphire substrates by 248nm KrF excimer laser ablation. The deposition rate as a function of laser fluence and O2 pressure at room temperature was measured with a quartz crystal microbalance. The results show different threshold fluences for deposition in vacuum vs. oxygen. While the deposition rate increases with increasing fluence at a given oxygen pressure, the rate eventually saturates at a higher laser fluence. At a given fluence, the oxygen pressure dependence of the deposition rate shows a radical reduction when the O2 pressure increases from 10 mTorr to 1 Torr. Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy were used to obtain stoichiometric information. A very strong pressure dependence of the O/Zr ratio was observed. While the trend of increasing O/Zr and Zr/Y ratio with increasing O2 pressure is apparent, the correlations between O/Zr as well as Zr/Y ratio and other processing conditions are less obvious. RBS results indicate an increasing roughness at the interface between the ZrO2 film and the sapphire substrate as the oxygen pressure exceeds 50 mTorr. The structural information obtained from x-ray diffraction patterns indicates broadening of peak width with increasing laser fluence as well as decreasing substrate temperature. For the film deposited at a lower substrate temperature, a strong (002) texture was observed.

Preparation of PZT/YBCO/YAIO Heterostructure Thin Films by KrF Excimer Laser Ablation

1998 ◽  
Vol 526 ◽  
Author(s):  
Kenji Ebihara ◽  
Hiromnitsu Kurogi ◽  
Yukihiko Yamagata ◽  
Tomoaki Ikegami ◽  
Alexander M. Grishin
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Excimer Laser ◽  
Ferroelectric Properties ◽  
Perovskite Oxide ◽  
Excimer Laser Ablation ◽  
Fatigue Characteristics ◽  
Krf Excimer Laser ◽  
Operation Frequency ◽  
Deposition Conditions

AbstractThe perovskite oxide YBa2Cu3O7-x (YBCO) and Pb(ZrxTi1-x)O3 (PZT) thin films have been deposited for superconducting-ferroelectric devices. KrF excimer laser ablation technique was used at the deposition conditions of 200-600mTorr O2, 2-3J/cm2 and 5-10 Hz operation frequency. Heterostructures of PZT-YBCO-YAlO3:Nd show the zero resistivity critical temperature of 82K and excellent ferroelectric properties of remnant polarization 32 μC/cm2, coercive force of 80kV/cm and dielectric constant 800. Cycling fatigue characteristics and leakage current are also discussed.

Preparation of PbZrxTi1−xO3 Thin Films by KrF Excimer Laser Ablation Technique

1996 ◽  
Vol 433 ◽  
Author(s):  
Hiromitsu Kurogi ◽  
Yukihiko Yamagata ◽  
Tomoaki Ikegami ◽  
Kenji Ebihara ◽  
Bok Yin Tong
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Excimer Laser ◽  
Oxygen Pressure ◽  
Ferroelectric Properties ◽  
Pzt Thin Films ◽  
Excimer Laser Ablation ◽  
Pzt Films ◽  
Krf Excimer Laser ◽  
Laser Ablation Technique

AbstractPb(ZrxTi1−x)O3(PZT) thin films have excellent ferroelectric, optical, piezoelectric and pyroelectric properties. We prepared PZT thin films using the excimer laser ablation technique. A pulsed KrF excimer laser was used to ablate PZT bulk targets. We have studied optimum preparation conditions such as an oxygen pressure, a laser energy fluence and a substrate temperature.In this paper, we investigated the composition, crystallization and ferroelectric properties of the PZT films prepared under various deposition conditions.The X-ray diffraction (XRD) patterns showed that the PZT films prepared on MgO(100) substrates at 600°C and with a laser fluence of 2J/cm2 had a perovskite - pyrochlore mixed structure. The condition of 100 mTorr oxygen pressure provided high quality perovskite films. It is found that the stoichiometric composition of the deposited films is obtained in ambient oxygen of 100˜400 mTorr. The ferroelectric properties of the Pt/PZT/Pt/MgO structure were studied. The capacitance-voltage characteristics and the corresponding hysteresis loop of the dielectric-electric field curve were discussed.We also studied optical emission of the PZT plasma plume to understand quantitative relation between the PZT film quality and the ablation plume plasma. We identified spectral lines originated in Pb, Pb+, Zr, Zr+, Ti, Ti+, PbO and TiO. These spectral intensities have remarkable dependence on the ambient O2 pressure.

Effects of Processing Parameters on KrF Excimer Laser Ablation Deposited ZrO2 Films

1991 ◽  
Vol 235 ◽  
Author(s):  
Gary A. Smith ◽  
Li-Chyong Chen ◽  
Mei-Chen Chuang
Keyword(s):  
Laser Ablation ◽  
Substrate Temperature ◽  
Excimer Laser ◽  
Deposition Rate ◽  
Oxygen Pressure ◽  
Pressure Dependence ◽  
Laser Fluence ◽  
X Ray ◽  
Excimer Laser Ablation ◽  
Krf Excimer Laser

ABSTRACTSystematic experiments have been carried out to characterize the yttria containing zirconia thin films on sapphire substrates by 248nm KrF excimer laser ablation. The deposition rate as a function of laser fluence and O2 pressure at room temperature was measured with a quartz crystal microbalance. The results show different threshold fluences for deposition in vacuum vs. oxygen. While the deposition rate increases with increasing fluence at a given oxygen pressure, the rate eventually saturates at a higher laser fluence. At a given fluence, the oxygen pressure dependence of the deposition rate shows a radical reduction when the O2 pressure increases from 10 mTorr to 1 Torr. Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy were used to obtain stoichiometric information. A very strong pressure dependence of the O/Zr ratio was observed. While the trend of increasing O/Zr and Zr/Y ratio with increasing O2 pressure is apparent, the correlations between O/Zr as well as Zr/Y ratio and other processing conditions are less obvious. RBS results indicate an increasing roughness at the interface between the ZrO2 film and the sapphire substrate as the oxygen pressure exceeds 50 mTorr. The structural information obtained from x-ray diffraction patterns indicates broadening of peak width with increasing laser fluence as well as decreasing substrate temperature. For the film deposited at a lower substrate temperature, a strong (002) texture was observed.

Clay Dispersion Effects on Excimer Laser Ablation of Polymer-Clay Nanocomposites

2011 ◽  
Author(s):  
I-Ta Chang ◽  
Erol Sancaktar
Keyword(s):  
Weight Loss ◽  
Laser Ablation ◽  
Absorption Coefficient ◽  
Excimer Laser ◽  
Threshold Fluence ◽  
Effective Absorption Coefficient ◽  
Excimer Laser Ablation ◽  
Air Atmosphere ◽  
Dispersion State ◽  
Krf Excimer Laser

The ablation behavior of Polystyrene-Organically Modified Montmorillonite (OMMT) nanocomposites was evaluated by measuring the weight loss induced by KrF excimer laser irradiation of the nanocomposite specimens under air atmosphere. The characteristic values of ablation, ablation threshold fluence and effective absorption coefficient for polystyrene and its naonocomposites were calculated based on the weight loss data. The effects of morphology due to spatial variation in injection molded samples are also discussed in this paper. Results demonstrate that both the dispersion state and the concentration of clay play important roles in excimer laser ablation. The sensitivity of threshold fluence and absorption coefficient to dispersion state of OMMT depends on the clay concentration.

Investigation of KrF excimer laser ablation and induced surface damage on lithium niobate

2002 ◽  
Vol 201 (1-4) ◽  
pp. 196-203 ◽  
Author(s):  
Han-Woo Chong ◽  
Arnan Mitchell ◽  
Jason P Hayes ◽  
Michael W Austin
Keyword(s):  
Laser Ablation ◽  
Lithium Niobate ◽  
Excimer Laser ◽  
Surface Damage ◽  
Excimer Laser Ablation ◽  
Krf Excimer Laser
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