• Hui Li

Articles written in Bulletin of Materials Science

• Synthesis and chemical etching of Te/C nanocables

In this paper, Te/C nanocables were fabricated by a hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB). The products were characterized in detail by multiform techniques: transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis and Fourier transform infrared (FTIR) spectroscopy. The results showed that the products were nanocables with lengths of several microns, core about 20 nm in diameter, and a surrounding sheath of about 60–80 nm in thickness. Te/C nanocables were tailored freely by chemical etching. Carbonaceous nanotubes and Te/C nanocables with fragmentary Te core were obtained by adjusting time of chemical etching.

• Initiatively embedding silver colloids in glass used in silver paste to improve metallization ohmic contact on silicon wafers

One of the decisive factors in realizing ohmic contact of silver (Ag) paste metallization on silicon (Si) wafers is the presence of Ag colloids in the glass phase at the Ag/Si interface. The Ag colloids are formed during the reaction between glass frit and Ag powder in the sintering process of Ag paste; thus, it is difficult to control the quantity of Ag colloids formed. In this study, we attempted to prepare a glass embedded with a large number of Ag colloids first to further improve the quality of ohmic contact of Ag paste metallization. In the PbO–TeO$_2$–SiO$_2$ glass system, a route was found for increasing the solubility of Ag in the glass melt by precipitating the Ce$_{1.88}$Pb$_{2.12}$O$_{6.53}$ crystal, which enabled a molar amount of recrystallized Ag colloids reach a high level of about $1/10$ of oxides in the glass. As a result, the esistivity of the Ag/Si contact can be decreased substantially. The formation mechanism of Ag colloids in glass isrevealed by various characterization and analysis methods, such as X-ray diffraction, electron energy loss spectroscopy, X-ray photoelectron spectroscopy, UV–visible and so on. Furthermore, it was also found that too high content of Ag in the glass melt would destroy the pyramid texture surface structure of Si wafers, which is not conducive to obtain high-quality Ag/Si ohmic contact. For this concern, optimal content of Ag colloids formed in glass is discussed.

• # Bulletin of Materials Science

Volume 45, 2022
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020