| 1 | Modeling on oxide dependent 2DEG sheet charge density and threshold voltage in AlGaN/GaN MOSHEMT显示文摘We have developed a physics based analytical model for the calculation of threshold voltage, two dimensional electron gas(2DEG) density and surface potential for Al Ga N/Ga N metal oxide semiconductor high electron mobility transistors(MOSHEMT). The developed model includes important parameters like polarization charge density at oxide/Al Ga N and Al Ga N/Ga N interfaces, interfacial defect oxide charges and donor charges at the surface of the Al Ga N barrier. The effects of two different gate oxides(Al_2O_3 and HfO_2/ are compared for the performance evaluation of the proposed MOSHEMT. The MOSHEMTs with Al_2O_3 dielectric have an advantage of significant increase in 2DEG up to 1.2 10^(13) cm^2 with an increase in oxide thickness up to 10 nm as compared to HfO_2 dielectric MOSHEMT. The surface potential for HfO_2 based device decreases from 2 to –1.6 e V within10 nm of oxide thickness whereas for the Al_2O_3 based device a sharp transition of surface potential occurs from 2.8to –8.3 e V. The variation in oxide thickness and gate metal work function of the proposed MOSHEMT shifts the threshold voltage from negative to positive realizing the enhanced mode operation. Further to validate the model,the device is simulated in Silvaco Technology Computer Aided Design(TCAD) showing good agreement with the proposed model results. The accuracy of the developed calculations of the proposed model can be used to develop a complete physics based 2DEG sheet charge density and threshold voltage model for Ga N MOSHEMT devices for performance analysis. | J.Panda K.Jena R.Swain T.R.Lenka | 2016 | Journal of Semiconductors2016，37，4： | 1 |
| 2 | High current limits in chemical vapor deposited graphene spintronic devices显示文摘Understanding the stability and current-carrying capacity of graphene spintronic devices is key to their applications in graphene channel-based spin current sensors,spin-torque oscillators,and potential spin-integrated circuits.However,despite the demonstrated high current densities in exfoliated graphene,the current-carrying capacity of large-scale chemical vapor deposited(CVD)graphene is not established.Particularly,the grainy nature of chemical vapor deposited graphene and the presence of a tunnel barrier in CVD graphene spin devices pose questions about the stability of high current electrical spin injection.In this work,we observe that despite structural imperfections,CVD graphene sustains remarkably highest currents of 5.2×10^(8)A/cm^(2),up to two orders higher than previously reported values in multilayer CVD graphene,with the capacity primarily dependent upon the sheet resistance of graphene.Furthermore,we notice a reversible regime,up to which CVD graphene can be operated without degradation with operating currents as high as 108 A/cm^(2),significantly high and durable over long time of operation with spin valve signals observed up to such high current densities.At the same time,the tunnel barrier resistance can be modified by the application of high currents.Our results demonstrate the robustness of large-scale CVD graphene and bring fresh insights for engineering and harnessing pure spin currents for innovative device applications. | Daria Belotcerkovtceva J.Panda M.Ramu Tapati Sarkar Ulrich Noumbe M.Venkata Kamalakar | 2023 | Nano Research2023，16，4： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员