Yonghong Li

Fabrication of oxidized multiwalled carbon nanotubes for the immobilization of U(VI) from aqueous solutions

Herein, the surface properties of oxidized multiwalled carbon nanotubes (MWCNs) were characterized by adopting XRD, SEM and FTIR. The sorption behaviors of U(VI) from wastewater by oxidized MWCNs were investigated by adopting batch technique. The experimental results demonstrated that sorption behaviors of U(VI) on oxidized MWCNs were dependent on ionic strength at low pH, and independent of ionic strength at high pH. The ion exchange and outer-sphere surface complexation were main mechanism for sorption of U(VI) on oxidized MWCNs at low pH, whereas inner-sphere surface complexation and coinstantaneous co-precipitation were primary mechanism at high pH.

Hot carrier effect on the bipolar transistors’ response to electromagnetic interference

Abstract Damage of bipolar transistors (BJTs) during the mission could affect their response to electromagnetic interference (EMI) and change the Integrated Circuit (IC)’s electromagnetic susceptibility (EMS). This work investigated the effect of hot carrier stress on BJT’s response to EMI. The experimental results demonstrate that the base current increases under EMI and the amplitude enlarges after hot carrier stress. The variation of EMI induced collector current shift after hot carrier stress depends on the base supply resistance Rt. When Rtxa0=xa00, I C shift in presence of EMI is not affected by hot carrier stress whereas in the case of Rtxa0≠xa00, the EMI induced I C increment reduces or even reverses in variation direction. When the base terminal is biased by a current source, the voltage across the emitter-base junction drops more significantly after hot carrier stress.

Time dependent modeling of single particle displacement damage in silicon devices

Abstract An approach combining molecular dynamics simulations with Kinetic Monte Carlo simulations is proposed to model the temporal evolution of single particle displacement damage in silicon. The three dimensional distributions of primary defects induced by Si recoils within 10xa0ps are obtained by molecular dynamics simulations and subsequently the long-term evolution (over 105xa0s) of multiple types of defects is simulated with Kinetic Monte Carlo technique fed by molecular simulation results. Based on classical Shockley–Read–Hall theory, the annealing factors of radiation-induced dark current related to the evolution of defects are predicted for photodiodes of 0.18xa0μm CMOS image sensors under neutron irradiation. The calculation results are consistent with the experimental data.

Measurement of single event effects induced by alpha particles in the Xilinx Zynq-7010 System-on-Chip

ABSTRACT Single event effect susceptibility of the Xilinx Zynq-7010 System-on-Chip (SoC) was investigated. Seven hardware blocks in the Zynq-7010 SoC were tested for single event effects using americium-241 alpha radiation source. Four error types, data error, single event upset and functional interrupt events, time-out, and system halt, were observed in different blocks under test. The dynamic cross sections of the different blocks were obtained and the reasons of some critical error types were analyzed.

Hot carrier effect on a single SiGe HBT's EMI response

Abstract This paper describes the rectification responses exhibited by two kinds of SiGe HBTs when electromagnetic interference (EMI) is injected at the base of the transistor. The variation of the EMI induced DC offset after hot carrier stress is also studied. The experimental results show that the EMI response of a single SiGe HBT is different from that of a Si BJT. With interference present, the DC current gain increases at low base-emitter (BE) bias and decreases at larger VBE values. The absence of AC crowding induced DC crowding along with the base recombination current accounts for the increase of current gain. The base-width effect and the high-injection effect tend to decrease the gain in presence of interference. The simulation results show that the Gummel–Poon model is able to quantitatively model the EMI response of a SiGe HBT.

Simulation of Heavy Ion Source-Drain Penetration Effect in SOI MOS and Bulk MOS

The Single Event Effects (SEE) of Silicon On Insulator (SOI) and bulk-silicon NMOS are simulated using the SENTAURUS-TCAD device simulator. The Source-Drain Penetration Effect, which is caused by a heavy ion, was shown. It is proved that when the feature size of device become less than a certain scale, both Direct Channel Effect and Indirect Channel Effect occur. By comparing the distributions of equipotential lines in the MOSFETs’ channels of the different feature size devices during the ion strikes indirectly, the Source-Drain-Penetration Effect occurs more evidently when the device feature size is getting smaller.Copyright