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.
This paper reports the microstructure and electrochemical properties of Si-Al-Fe ternary amorphous alloys prepared by rapid solidification as an anode for lithium secondary batteries. The microstructure was analyzed using XRD and HR-TEM with EDS mapping. In accordance with DSC analysis, annealing was performed to crystallize the active nano-Si in the amorphous alloy. Thus, nano-Si forms (~80 nm) embedded in the matrix alloy, such as Fe2Al3Si3, FeSi2, and Fe0.42Si2.67, were successfully synthesized. The electrode based on the Si-Al-Fe ternary alloy delivered an initial discharge capacity of approximately 700 mAh g-1, and exhibited a high Coulombic efficiency of 99.0~99.6% from the 2nd to 70th cycles.
We prepared SnSx thin films on both soda-lime glass (SLG) and molybdenum(Mo)/SLG substrates by a two-step process using a Sn precursor followed by sulfur reaction in rapid thermal annealing (RTA) at different sulfurization temperatures (Ts = 200℃, 230℃, 250℃, and 300℃) and annealing times (ts = 10 min and 30 min). The single SnS phase was dominant for 200℃≤Ts<250℃, while an additional phase of SnS2 was appeared at Ts≥250℃ alongside SnS. The SnS grains in all the samples showed strong growth along the preferred [040] direction. The band-gap energy (Eg) of the films was estimated to be 1.24 eV.
Using both EVA and POE encapsulants, we fabricated polycrystalline Si PV modules and performed a set of reliability tests of PID, DH, TC, and Complex prior to outdoor installation. The power output with temperatures and insolation as well as I-V characteristics had been monitored under outdoor environments for 18 months. In the entire period, the total power of 3,576 kWh from POE PV modules was observed larger than 3,449 kWh from EVA PV modules by 3.5%. All the PV modules showed a 5.6~9.2% drop in the conversion efficiency. As for the solar power generation, the PV modules performed through PID, TC test revealed distinct difference in between EVA and POE for which the POE PV module produced more power by +11.4% and +6.6%, respectively, as measured in the 18th month. In addition, POE was proved to protect better the solar cells under PID influence.
We fabricated a tin sulfide (SnS) layer with Sn/Mo/glass layers followed by a RTP (rapid thermal processing), and studied the film growth and structural characteristics as a function of annealing temperature and time. The elemental sulfur (S) was cracked thermally and applied to form SnS polycrystalline film out of the Sn percursor at pre-determined pressures in the RTP tube. The sulfurization was done at the temperature from 200℃ to 500℃ for a time period of 10 to 40 min. At ≤ 300℃, 20 min., p-type SnS thin films was grown and showed the best composition of at.% of [S]/[Sn] . 1 and [111] preferred orientation as investigated from using XRD (X-ray diffraction) analysis and EDS (energy dispersive spectroscopy) and SEM (scanning electron microscopy), and optical absorption by a UV-VIS spectrometer. In this paper, we report the details of growth characteristics of single phase SnS thin film as a function of annealing temperature and time associated with the pressure and ambient gas in the RTP tube.
In this paper, TiO2 based thin-film transistors (TFTs) were fabricated using by an atomic layer deposition with high aspect ratio and excellent step coverage. Ti02 semiconducting layer was deposited showing a rutile phase through the rapid thermal annealing process, and exhibited TFT characteristics with a 200 pm channel length of low-leakage currents (none of current flow during off-state), stable threshold voltages (-10 V - 0 V), and a much higher on/off current ratio (
Because the Pb-based piezoelectric materials showed problems such as an environmentalpollution. lead-free ZnSnO3 materials were studied in the present study. The ZnSnO3 thin films weredeposited at 640℃ on Pt/Ti/SiO2 substrate by pulsed laser deposition (PLD) and were annealed for 5 minat 750℃ using rapid thermal annealing (RTA) in nitrogen atmosphere. Samples annealed at 750℃ showeda smooth morphology and an improvement of the dielectric and leakage properties, as compared withas-grown samples. However, electrical properties of the ZnSnO3 thin films obtained in the present studyshould be improved for piezoelectric applications.
PID (potential induced degradation) of PV module is the degradation of module due to the high potential difference between the front surface of solar cells and ground when PV modules operate under high humidity and temperature conditions. PID is generally derived from the positive sodium ions in front glass that are accumulated on P-type solar cells. Therefore, some papers for the electrical characteristic of only front components as glass, EVA sheet, solar cell under PID generation condition were revealed. In this paper, we analyzed the different outputs of module with PID by considering the all parts of module including the back side elements such as glass, back sheet. Mini modules with one solar cell were fabricated with the various parts on front and back sided of module. To generate PID of module in a short time, the all modules were applied?1,000 V in 85℃, 85% RH. The outputs, dark IV curves and EL images of all modules before and after experiments were also measured to confirm the main components of module for PID generation. From the measured results, the outputs of all modules with front glass were remarkably reduced and the performances of modules with back and front glass were greatly deteriorated. We suggest that the obtained data could be used to reduce the PID phenomenon of diverse modules such as conventional module and BIPV (building integrated photovoltaic) module.
SiO2 layer grown by rapid thermal oxidation and SiNx layer were used for passivating the surface of n-type silicon solar cell, instead of only SiNx layer generally used in photovoltaic industry. The rapid thermal oxidation provides the reduction of processing time and avoids bulk life time degradation during the processing. Improvement of 30 mV in Voc and 2.7 mA/cm2 in Jsc was obtained by applying these two layers. This improvement led to fabrication of a large area (239 cm2) n-type solar cell with 17.34% efficiency. Internal quantum efficiency measurement indicates that the improvement comes from the front side passivation, but not the rear side, by using SiO2/SiNx stack.
In this study, transparent conducting Al-doped Zinc Oxide (AZO) films with a thickness of 150 nm were prepared on corning glass substrate by the RF magnetron sputtering with using a Al-doped zinc oxide (AZO), (Al2o3: 2 wt%) target at room temperature. This study investigated the effect of rapid thermal annealing temperature and oxygen ambient on structural, electrical and optical properties of Al-doped zinc oxide (AZO) thin films. The films were annealed at temperatures ranging from 400 to 700℃ by using Rapid thermal equipment in oxygen ambient. The effect of RTA treatment on the structural properties were studied by x-ray diffraction and atomic force microscopy. It is observed that the Al-doped zinc oxide (AZO) thin film annealed at 500℃ at 5 minute oxygen ambient gas reveals the strongest XRD emission intensity and narrowest full width at half maximum among the temperature studied. The enhanced UV emission from the film annealed at 500℃ at 5 minute oxygen ambient gas is attributed to the improved crystalline quality of Al-doped zinc oxide (AZO) thin film due to the effective relaxation of residual compressive stress and achieving maximum grain size.
Graphene was fabricated onto Ni/Si substrate using a rapid-thermal pulse CVD and they were transferred onto the Ti/PES flexible substrate. For top electrode applications of the BMNO dielectric films, graphene was patterned using a argon plasma. Through an AFM image and a leakage current density of the BMNO films grown onto various bottom electrodes before and after bending test, BMNO films grown onto the graphene bottom electrode showed no change of the microstructure and the leakage current density after the bend.
Even though nano-scale materials were very advantageous for various applications, there are still problems to be solved such as the stabilization of surface state and realization of low contact resistances between a semiconducting nanowire and electrodes in nano-electronics. It is well known that the effects of contacts barrier between nano-channel and metal electrodes were dominant in carrier transportation in individual nano-electronics. In this report, it was investigated the electrical properties of GaN nanorod devices after chemical etching and rapid thermal annealing for making good contacts. After KOH wet-etching of the contact area the devices showed better electrical performance compared with non-treated GaN individual devices but still didn`t have linear voltage-current characteristics. The shape of voltage-current properties of GaN devices were improved remarkably after rapid thermal annealing as showing Ohmic behaviors with further bigger conductivities. Even though chemical etching of the nanorod surfaces could cause scattering of carriers, in here it was shown that the most important and dominant factor in carrier transport of nano-electronics was realization of low contact barrier between nano-channel and metal electrodes surely.
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