Aluminum-induced crystallization (AIC) as a route to reduce the fabrication cost and to obtain polycrystalline Si (p- Si) thin-film of large grain size is a promising alternative of single-crystalline (s-Si) substrate or p-Si thin-film obtained by conventional methods such as solid phase crystallization (SPC) and laser-induced crystallization (LIC). As the AIC process occurs at the interface between a-Si and Al thin-films, there are various process and interface parameters. Also, it directly means that there is a certain parametric window to obtain p-Si of large grain size having uniform crystal orientation. In this article, we investigate the effect of the various process and interface parameters to obtain p-Si of large grain size and uniform crystal orientation from the literature review. We also suggest the potential use of the p-Si as a virtual substrate for the growth of various compound semiconductors in a form of low-dimension as well as thin-film as a way for their monolithic integration on Si.
The Ga2O3 thin films were deposited using an RF sputtering system and the effect of crystallographic and optical properties under rapid thermal annealing conditions on Ga2O3 thin film was evaluated. A rapid thermal annealing method can fabricate a crystalline Ga2O3 thin film which is applied to various fields with a low cost and a high efficiency compared with the conventional post-annealing method. In this study, the Ga2O3 treated at 900℃ for 1 min showed the beta and gamma phases in XRD measurement. In optical properties, the crystalline Ga2O3 represented a high transmittance of more than 80% in the visible region and was calculated with a high optical bandgap energy of 4.58 eV. The beta and gamma phases Ga2O3 can be obtained by adjusting the rapid thermal annealing temperatures, and the various properties such as the optical bandgap energy can be controlled. Moreover, it is expected that crystalline Ga2O3 can be applied to various devices by controlling not only temperature but process time.
Perovskite materials are promising candidates for next-generation optoelectronic devices owing to their outstanding external quantum efficiency, high color purity, and ability to tune the light emission wavelength. However, conventional thermal annealing processes caused the degradation of perovskite, resulting in poor optoelectronic properties and a short lifetime. Herein, we propose a laser-induced recrystallization of perovskite thin film to enhance its light-emitting properties. Laser-induced recrystallization process was performed using rapid and instantaneous laser heating, which successfully induced grain growth of the perovskite material. The laser processing conditions were thoroughly optimized based on theoretical calculations and various material analyses such as x-ray diffraction, scanning electron microscope, and photoluminescence spectroscopy.
In this paper, we study the correlation between the crystallinity of semiconductive compounds for eco-friendly power cables and the dispersive properties of carbon black. The crystal structure of the polymer material is advantageous for mechanical properties and heat-resistance. However, the polymer acts as an inhibitor to the dispersibility of carbon black. The purpose of this study is to develop a TPE semiconductive compound technology. The high heat resistance and ultra-smoothness characteristics which are required for high voltage and ultra-high voltage cables should be satisfied by designing and optimizing the structure of a non-crosslinking-type eco-friendly TPE semiconductive compound. The application of excess TPE resin was found to not only inhibit the processability in the compounding process, but also reduced the dispersion properties of carbon black due to higher crystallinity. After the crystallinity of the compound was identified through DSC analysis, it was compared with the related dispersion characteristics. Through this analysis and comparison, we designed the optimal structure of the eco-friendly TPE semiconductive compound.
Glass ceramic has a high mechanical strength and low sintering temperature. So, it can beused as a thick film substrate or a high strength insulator. A series of glass ceramic samples based onMgO-Al2O3-SiO2-ZrO2 (MASZ) were prepared by melting at 1,600℃, roll-quenching and heat treatment atvarious temperatures from 900℃ to 1,400℃. Dependent on the heat treatment temperature used, glassceramics with different crystal phases were obtained. Their nucleation behavior, microstructure andmechanical properties were investigated with differential thermal analysis (DTA), X-ray diffraction (XRD),scanning electron microscopy (SEM), and Vicker`s hardness testing machine. With increasing the heattreatment temperature of MASZ samples, their hardness and toughness initially increase and then reachthe maximum points at 1,300℃, and begin to decrease at above this temperature, which is likely to bedue to the softening of glass ceramics. As the content of ZrO2 in MAS glass ceramics increases from 7.0wt.% to 13 wt.%, Vicker`s hardness and fracture toughness increase from 853 Kg/mm2 to 878 Kg/mm2and 1.6 MPa??m1/2 to 2.4 MPa??m1/2 respectively, which seems to be related with the nucleation of elongatedphases like fiber.
In this study, Ge8Se(2+x)Te(6-x) thin film amorphous-to-crystalline phase-change rate was evaluated in using a nano-pulse scanner. The focused laser beam with a diameter <10 μm was illuminated in the power (P) and pulse duration (t) ranges of 1-31 mW and 10-460 ns, respectively, with subsequent detection of the responsive signals reflected from the film surface. We also evaluated the material characteristics, such as optical absorption and energy gap, crystalline phases, and sheet resistance of as-deposited and annealed films. The result of experiments showed that the thermal stability of the Ge-Se-Te film is largely improved by adding Se.
Amorphous Si (a-Si) thin films of p+/p-/n+ were deposited on Si3N4/glass substrate by using a plasma enhanced chemical vapor deposition (PECVD) method. These films were annealed at various temperatures and for various times by using a rapid thermal process (RTP) equipment. This step was added before the main thermal treatment to make the nuclei in the a-Si thin film for reducing the process time of the crystallization. The main heat treatment for the crystallization was performed at the same condition of 600℃/18 h in conventional furnace. The open-circuit voltages (Voc) were remained about 450 mV up to the nucleation condition of 16min in the nucleation RTP temperature of 680℃. It meat that the process time for the crystallization step could be reduced by adding the nucleation step without decreasing the electrical property of the thin film Si for the solar cell application.
In this paper, experimental analyses have been performed to compare the electrical characteristics of n channel LT(low temperature) and HT(high temperature) poly-Si TFTs(polycrystalline silicon thin film transistors) on quartz substrate according to activated step annealing. The size of the particles step annealed at low temperature are bigger than high temperature poly-Si TFTs and measurements show that the electric characteristics those are transconductance, threshold voltage, electric effective mobility, on and off current of step annealed at LT poly-Si TFTs are high more than HT poly-Si TFT`s. Especially we can estimated the defect in the activated grade poly crystalline silicon and the grain boundary of LT poly-Si TFT have more high than HT poly-Si TFT`s due to high off electric current. Even though the size of particles of step annealed at low temperature, the electrical characteristics of LT poly-Si TFTs were investigated deterioration phenomena that is decrease on/off current ratio depend on high off current due to defects in active silicon layer.
Poly Si TFTs (poly silicon thin film transistors) with p channel those are annealed HT (high t emperature) with gate poly crystalline silicon and LT (low temperature) with metal gate electrode were fabricated on quartz substrate using the analyzed data and compared according to the activated grade silicon thin films and the size of device channel. The electrical characteristics of HT poly-Si TFTs increased those are the on current, electron mobility and decrease threshold voltage by the quality of particles of active thin films annealed at high temperature. But the on/off current ratio reduced by increase of the off current depend on the hot carrier applied to high gate voltage. Even though the size of the particles annealed at low temperature are bigger than HT poly-Si TFTs due to defect in the activated grade poly crystal silicon and the grain boundary, the characteristics of LT poly-Si TFTs were investigated deterioration phenomena those are decrease the electric off current, electron mobility and increase threshold voltage. The results of transconductance show that slope depend on the quality of particles and the amplitude depend on the size of the active silicon particles.
An amorphous Ge2Sb2Te5 thin film is one of the most commonly used materials for phase-change data storage. In this study, Aux(Ge2Sb2Te5)1-x thin film amorphous-to-crystalline phase-change rate were evaluated in using 658 nm laser beam. The focused laser beam with a diameter <10 μm was illuminated in the power (P) and pulse duration (t) ranges of 1-17 mW and 10-460 ns, respectively, with subsequent detection of the responsive signals reflected from the film surface. We also evaluated the material characteristics, such as optical absorption and energy gap, crystalline phases, and sheet resistance of as-deposited and annealed films. The result of experiments showed that the thermal stability of the Ge2Sb2Te5 film is largely improved by adding Au.
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