Transient Photoconductivity of GaN Thin Film On Sapphire Substrate

1998 ◽  
Vol 512 ◽  
Author(s):  
Z. Z. Chen ◽  
B. Shen ◽  
R. Zhang ◽  
X. Y. Zhang ◽  
K. Yang ◽  
...  
Keyword(s):  
Thin Film ◽  
Valence Band ◽  
Sapphire Substrate ◽  
Pulsed Laser ◽  
Valence Band Edge ◽  
Trapping Level ◽  
Time Constants ◽  
Hole Trapping ◽  
Transient Photoconductivity ◽  
Deep Traps

ABSTRACTWe studied the transient photoconductivity(PC) properties of GaN thin film on (0001) sapphire substrate. The decay curves of PC obtained by YAG:Nd pulsed laser are divided into two special regions, which are the beginning and tail decay regions, corresponding to two time constants, 0.1 ms and 1.0 ms, respectively. Keeping the same light intensity and bias voltage, when the sample was heated to 300°C, the time constants are both reduced. It shows that there are a large number of traps at the position of tens of meV above the valence band edge. The PC ascends S-shaped when the data were collected during the first 200 ns. As the sample is not shined, the PC sharply reduces and oscillates, indicating that the carriers redistributed between the deep traps and the valence band. The experiment results are explained by the model that involves two hole trapping levels, the shallow trapping level and the deep trapping level. Moreover, the mechanism of the curves varied as the light intensities are also explained by the model.

Pulsed laser deposition of ilmenite FeTiO 3 epitaxial thin film onto sapphire substrate

1999 ◽  
Vol 339 (1-2) ◽  
pp. 114-116 ◽  
Author(s):  
Zhongning Dai ◽  
Peiran Zhu ◽  
Shunya Yamamoto ◽  
Atsumi Miyashita ◽  
Kazumasa Narum ◽  
...  
Keyword(s):  
Thin Film ◽  
Pulsed Laser Deposition ◽  
Sapphire Substrate ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Epitaxial Thin Film

TEM Observation and Ionic Conductivity Study of Li2SiO3 Thin-Film on Sapphire Substrate

2013 ◽  
Vol 596 ◽  
pp. 15-20 ◽  
Author(s):  
Shinichi Furusawa ◽  
Takao Tsurui ◽  
Kouhei Shimizu
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Ionic Conductivity ◽  
Temperature Dependence ◽  
Sapphire Substrate ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Temperature Range ◽  
Transmission Electron ◽  
Lithium Ionic Conductor

Thin-film samples of the lithium ionic conductor Li2SiO3(LSO) were deposited on an A-plane sapphire substrate via the pulsed laser deposition (PLD) method, and the irreversible temperature dependence of the ionic conductivity in the thin-film samples was studied. Via transmission electron microscopy (TEM) observations of annealed LSO thin-film, it was found that the as-prepared LSO thin-film was amorphous over the temperature rangeT490 K, and that nanocrystals existed in the annealed LSO thin-film in the temperature rangeT550 K. Further more, it was clarified the irreversible temperature dependence of the ionic conductivity is due to the generation of nanocrystals.

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

scholarly journals Devitrification of thin film Cu-Zr metallic glass via ultrashort pulsed laser annealing

2021 ◽  
pp. 161437
Author(s):  
J. Antonowicz ◽  
P. Zalden ◽  
K. Sokolowski-Tinten ◽  
K. Georgarakis ◽  
R. Minikayev ◽  
...  
Keyword(s):  
Thin Film ◽  
Metallic Glass ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Pulsed Laser Annealing ◽  
Ultrashort Pulsed Laser
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