Insights into channel potentials and electron quasi-Fermi potentials for DG tunnel FETs

A detailed investigation carried out, with the help of extensive simulations using the TCAD device simulator Sentaurus, with the aim of achieving an understanding of the effects of variations in gate and drain potentials on the device characteristics of a silicon double-gate tunnel field effect transistor（Si-DG TFET） is reported in this paper. The investigation is mainly aimed at studying electrical properties such as the electric potential, the electron density, and the electron quasi-Fermi potential in a channel. From the simulation results, it is found that the electrical properties in the channel region of the DG TFET are different from those for a DG MOSFET. It is observed that the central channel potential of the DG TFET is not pinned to a fixed potential even after the threshold is passed（as in the case of the DG MOSFET）; instead, it initially increases and later on decreases with increasing gate voltage, and this is also the behavior exhibited by the surface potential of the device. However, the drain current always increases with the applied gate voltage. It is also observed that the electron quasi-Fermi potential（e QFP）decreases as the channel potential starts to decrease, and there are hiphops in the channel e QFP for higher applied drain voltages. The channel regime resistance is also observed for higher gate length, which has a great effect on the I–V characteristics of the DG TFET device. These channel regime electrical properties will be very useful for determining the tunneling current; thus these results may have further uses in developing analytical current models.

Feeding behavior explains the different effects of cabbage on MEAM1 and MED cryptic species of Bemisia tabaci

MEAMI(Middle East-Asia Minor 1."B"biotype)anpl MED(Mediterranean,"Q"biotype)are the two most destructive ery pie species of the Bemisia tabaci complex on the planet.Our previous studies have shown that MEAMI outcompets MED on cabbage;the underlying mechanism is unknown.In the Brassicaceae family,the glucosinolate-myrosinase defense system plays a crucial role im deterring feeding,inhibiting growth,and eausing acute toxicity against a wide range of generalist herbivores.In the present study.we first compared the surv ival of MEAMI and MED exposed to sinigin(a glucosinolate)and myosinase(an enzyme that degrades glucosinolates);we found that survival of both species was high in response 10 sinigrin alone bul was near zer0 in response to sinigrin+myrosinase.We then used electropenetrography(lectrical penetration graphs,EPG)to assess the feeding bchaviors of MEAMI and MED whiteflies on cabbage.The EPG results revealed that the me an dunution of each potential drop(pd,indicating an intreellular puncture)was subsantialy longer for MED than MEAMI on eabbage,indicating that the exposure to the toxic hydrolysates of glucosinolate and myrosinase is greater for MED than for MEAMI.We therefore conclude that dffreces in penetrating bchaviors may help explain the dfferent fiects of cabbuge on MEAMI and MED whitefly species.