A novel diode-pumped solid-state continuous-wave (CW) laser technology has been demonstrated for high-performance low-temperature polycrystalline silicon thin-film transistors (TFTs) fabrication. The CW laser-crystallized (CWC) poly-Si thin films indicated the excellent crystallinity with the flat surface morphology at grain boundary. Besides, the CW laser activation is a low-thermal budget process and can achieve the lower sheet resistance of 50 Ω/□ and uniformly redistributed dopant profiles. The n-channel CWC TFTs revealed the superior field-effect mobility reaching 505 cm2/V-s and the lower subthreshold swing as compared with the conventional excimer laser-crystallized ones.
The structure stability、micro-structure and electrical properties of lithium doping on potassium sodium niobate ceramics (Na0.5K0.5)NbO3 (NKN) were investigated in this study. Solid oxide mixing method with post calcination and sintering was employed to fabricate(Na0.5K0.5)(1-x) LixNbO3 ceramic. Lithium oxide was adopted as the sintering aids. For Li doping x=6 mol% in (Na0.5K0.5)(1-x) LixNbO3 ceramic a optimal crystallization and electrical properties could be achieved after 650°C calcination and 1060°C sintering. Ferroelectric properties of the lead-free ceramic behaved a coercive field of 12.5kV/cm and remanent polarization as high as 30uC/cm2.
A small-size printed antenna is proposed for the application of mobile phones. The antennacomprisesan outer strip, an inner strip, and a common section.It not only occupies a compact area of 25 × 20 mm² butalsosupports two wide bandswithinthe resonantmodes. Prototypes of the antenna had been constructed and experimentally verified. The measured results of the antenna show the bandwidth cover the existing service bands of GSM/DCS/PCS/UMTS within 6 dB return loss specification, and also have good radiation patterns and antenna gains.This antenna is well suitable to be used for mobile phone application.
With the rapid development of the wireless communications, the quality of wireless communications services are increasingly improved, which makes people to pay more attention to efficiency and effectiveness of wireless communication system. Recently, some popular portable devices are those defined by 802.11b, 802.11g and 802.11n protocols, such as Wi-Fi card, Wi-Fi card reader and Wi-Fi hard disk. A dual frequency WLAN antenna used for applications of Wi-Fi portable devices is necessary. The reflection loss (Return Loss) of the antenna is a key parameter, therefore, the antenna return loss and bandwidth must meet the conditions of requirements. We use electromagnetic simulation software to simulate and tune the reflection loss of the antenna to more than 10 dB specification. According to the parameters of simulation results, a dual frequency WLAN antenna used for applications of Wi-Fi portable devices is fabricated.
High performance and device uniformity n-channel low-temperature poly-silicon (LTPS) bottom-gate (BG) thin film transistors (TFTs) with artificially-controlled lateral grain growth have been performed by excimer laser crystallization (ELC). The BG TFTs (W/L = 1.5 μm/1.5 μm) demonstrate field-effect-mobility of 323 cm2/Vs and high Ion/Ioff of 9.5 × 108. The proposed BG TFTs reveal the superior electrical characteristics, device uniformity, and reliability than conventional top-gate ones.
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