Improved double-gate armchair silicene nanoribbon field-effect-transistor at large transport bandgap

The electrical characteristics of a double-gate armchair silicene nanoribbon field-effect-transistor （DG ASiNR FET） are thoroughly investigated by using a ballistic quantum transport model based on non-equilibrium Green＇s function （NEGF） approach self-consistently coupled with a three-dimensional （3D） Poisson equation. We evaluate the influence of variation in uniaxial tensile strain, ribbon temperature and oxide thickness on the on-off current ratio, subthreshold swing, transconductance and the delay time of a 12-nm-length ultranarrow ASiNR FET. A novel two-parameter strain mag- nitude and temperature-dependent model is presented for designing an optimized device possessing balanced amelioration of all the electrical parameters. We demonstrate that employing HfO2 as the gate insulator can be a favorable choice and simultaneous use of it with proper combination of temperature and strain magnitude can achieve better device performance. Furthermore, a general model power （GMP） is derived which explicitly provides the electron effective mass as a function of the bandgap of a hydrogen passivated ASiNR under strain.

Electrolyte-gated SrCoO_(x) FET sensor for highly sensitive detecting pH in extreme alkalinity solution

The pH monitoring is significantly important in chemical industry,biological process,and pollution treatment.However,it remains a great challenge to measure pH in extreme alkalinity conditions.Herein,we employ an electrolyte-gated field-effect-transistor(FET)strategy using non-stoichiometric SrCoO_(x) with rich oxygen-vacancy defects as channel materials for detecting extreme alkalinity.The corresponding channel can provide effective oxygen-ion-migration sites for reversible transformation of OH-↔O_(2)-+H^(+)driven by electric field.The resultant electrolyte-gated FET sensor exhibits a sensitive linear response to high concentrations of alkaline solution,1–20 M.Significantly,the sensor has the ability to directly indicate the pH values ranging from 14.0 to 17.0 in consideration of ion-activity coefficient data.This work offers a great possibility for directly detecting base concentration as well as pH values in extreme alkaline solutions.

Tuning the inhomogeneous charge transport in ZnO interfaces for ultrahigh on/off ratio top-gated field-effect-transistor arrays

The interface between oxide/oxide layers shows an inhomogeneous charge transport behavior,which reveals a high conductivity owing to interface-doped.One typical example is the hetero-interface between ZnO film and other wide band gap oxides(e.g.,Al_(2)O_(3),TiO_(2),and HfO_(2)).It is thus quite evident that the ZnO/other oxides hetero-interface contains high density electron carriers effectively screening the gate-induced electric field.Thus,an extremely weak gate modulation in ZnO film was showed,resulting in very low on/off ratio of 1.69 in top-gate field-effect-transistor(TG-FET)configuration.So,to extend the usage of ZnO TG-FET is not quite possible toward further practical application.Herein,we clarified the correlation of inhomogeneous region in oxide/oxide hetero-junction by systematically study.Our work suggests that a self-assembly of molecules(SAM)buffer layer is suitable for tuning the inhomogeneous charge transport in ZnO film,which not only reduces the interface trap density,but also effectively enhances the gate electric field modulation at the hetero-interface.We further report the robust fabrication of TG-FET arrays based on ZnO thin film,using an ultra-thin alkylphosphonic acid molecule monolayer as buffer layer.Our device demonstrates a pronounced ultrahigh on/off ratio of≥10^(8),which is 8-order of magnitude higher than that of a device without buffer layer.For the highly reliable arrays,our device exhibits a high yield of over 93%with an average on/off ratio of^10^(7) across the entire wafer scale,mobility(18.5 cm^(2)/(V·s)),an extended bias-stressing(~2,000 s)and long-stability(~150 days)under ambient conditions.

Temperature dependent I_(DS)–V_(GS) characteristics of an N-channel Si tunneling field-effect transistor with a germanium source on Si(110) substrate

We fabricated n-type Si-based TFETs with a Ge source on Si（110） substrate. The temperature dependent IDS-VGS characteristics of a TFET formed on Si（110） are investigated in the temperature range of 210 to 300 K. A study of the temperature dependence of/Leakage indicates that/Leakage is mainly dominated by the Shockley-Read- Hall （SRH） generation-recombination current of the n＋ drain-Si substrate junction, ION increases monotonically with temperature, which is attributed to a reduction of the bandgap at the tunneling junction and an enhancement of band-to-band tunneling rate. The subthreshold swing S for trap assisted tunneling （TAT） current and band-to- band tunneling （BTBT） current shows the different temperature dependence. The subthreshold swing S for the TAT current degrades with temperature, while the S for BTBT current is temperature independent.