دانلود رایگان ترجمه مقاله ترانزیستورهای اثر میدانی تونل زنی نانونوار گرافنی با یک کانال ناهمگن نیمه فلزی – IEEE 2012
دانلود رایگان مقاله انگلیسی + خرید ترجمه فارسی | |
عنوان فارسی مقاله: |
ترانزیستورهای اثر-میدانی تونل زنی نانوروبان گرافن با یک نیمه هادی و کانال نیمه فلزی ناهمگون |
عنوان انگلیسی مقاله: |
Graphene Nanoribbon Tunneling Field-Effect Transistors With a Semiconducting and a Semimetallic Heterojunction Channel |
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مشخصات مقاله انگلیسی (PDF) | |
سال انتشار | ۲۰۱۲ |
تعداد صفحات مقاله انگلیسی | ۸ صفحه با فرمت pdf |
رشته های مرتبط با این مقاله | مهندسی برق |
گرایش های مرتبط با این مقاله | مهندسی الکترونیک، مدارهای مجتمع الکترونیک، الکترونیک قدرت و ماشینهای الکتریکی |
چاپ شده در مجله (ژورنال) | یافته ها در حوزه دستگاه های الکترونیکی – TRANSACTIONS ON ELECTRON DEVICES |
کلمات کلیدی | گرافن، ناهمگون، ترانزیستورهای تونل زنی |
ارائه شده از دانشگاه | گروه مهندسی برق و کامپیوتر، دانشگاه ملی سنگاپور |
رفرنس | دارد ✓ |
کد محصول | F1003 |
نشریه | آی تریپل ای – IEEE |
مشخصات و وضعیت ترجمه فارسی این مقاله (Word) | |
وضعیت ترجمه | انجام شده و آماده دانلود |
تعداد صفحات ترجمه تایپ شده با فرمت ورد با قابلیت ویرایش | ۱۸ صفحه با فونت ۱۴ B Nazanin |
ترجمه عناوین تصاویر | ترجمه شده است ✓ |
ترجمه متون داخل تصاویر | ترجمه نشده است ☓ |
درج تصاویر در فایل ترجمه | درج شده است ✓ |
منابع داخل متن | به صورت عدد درج شده است ✓ |
کیفیت ترجمه | کیفیت ترجمه این مقاله متوسط میباشد |
فهرست مطالب |
چکیده
۱٫ مقدمه
۲٫ رویکردهای شبیه سازی
۳٫ نتایج و بحث
A. اثر ابعاد منطقه HJ
B. اثر GC بر منطقه HJ
۴٫ نتیجه گیری
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بخشی از ترجمه |
چکیده ۱٫ مقدمه |
بخشی از مقاله انگلیسی |
Abstract We present a computational study of the device performance of graphene nanoribbon tunneling field-effect transistors (TFETs) with a heterogeneous channel. By varying the length and the energy bandgap (EG) of the heterogeneous region, the ON- and OFF-state currents (ION and IOFF) can be effectively optimized independently. Both semiconducting and semimetallic heterogeneous regions are studied to understand the effects of EG engineering on device behaviors. In addition, the effect of gate coverage (GC) over the heterogeneous region is also investigated. We found that device performance is greatly affected by the positioning of the gate to modify the region where band-to-band tunneling occurs. For a given ION/IOFF of eight orders, our results show that, for the semiconducting heterojunction, a higher ION can be obtained by having the gate partially covering the heterogeneous region. This is due to a combination of a short tunneling length and resonant states, which leads to an increase in carrier concentration for the tunneling mechanism. On the other hand, for the semimetallic case, a similar ION/IOFF is only attainable when the heterogeneous region is not covered by the gate. A large IOFF is observed for even small GC due to the valence electrons from the source traveling to the conduction bands of the semimetallic region, enhancing the carrier transport toward the drain. Our study highlights the device design consideration required when optimizing the device performance of heterojunction TFETs. I. INTRODUCTION GRAPHENE is a 2-D zero energy bandgap (EG) material, whose carriers behave as massless fermions. Their energy dispersion near Fermi level is linear and can be approximated with the Dirac equation [1]. It exhibits many novel properties that are not observed in conventional materials, such as the Klein paradox in a p-n junction and the quantum spin Hall effect [2], [3], which can enable new functional devices. As both the electrons and the holes have similar electronic properties, graphene can be used for n- and p-type field-effect transistors (FETs) with similar performance. These unique characteristics make graphene a potential successor to silicon in nanoelectronic devices as silicon approaches its fundamental limitations with the continuing miniaturization of device sizes [4]. In particular, due to its single-layer structure and compatibility with complementary metal–oxide–semiconductor technology, graphene’s application in FETs has been experimentally demonstrated using graphene obtained by micromechanical cleavage of pyrolytic graphite [5]. While the absence of a sizable EG seriously restricts the potential of a graphene FET in digital applications [6]–[۱۰], a couple of novel functional devices exploiting other novel properties have been proposed. For example, the quantum reflective switch [11] based on the Klein paradox and the Veselago lens in graphene p-n junctions exploiting its electron-optic behaviors [12] have garnered much interest in the device community. Nevertheless, much research effort has been focused on exploring how to open a usable EG in graphene, such as by breaking the sublattice symmetry and by chemical functionalization [13], [14]. Among these methods, the reduction in dimensionality in graphene nanostructures, for example, carbon nanotubes (CNTs) and graphene nanoribbons (GNRs), has been found to be an effective way to induce EG [15], [16]. For GNRs, the value of EG is dependent on the ribbon width and is highly sensitive to an external stimulus, such as strain and electric field. As a result, GNRs enable a wide spectrum of tunable electronic devices [15]–[۱۹]. From the device community, the current–voltage (I–V ) characteristics of various graphene nanostructures have been reported [20]–[۲۲] with promising potentials in FET applications. Although device performance of such fabricated FETs will be adversely affected by edge roughness [23], [24], GNR FETs are still considered as one of the most promising tunneling FETs (TFETs) [25]–[۳۶] due to their low tunneling mass, direct bandgap, and compatibility with planar processing. A heterogeneous junction (HJ) in a GNR has been introduced as a means to enhance the performance of GNR FETs. One such type of HJ TFET is by combining GNRs of different widths in the channel region, and its ability to improve the ON-state current (ION) and the ON-state/OFF-state current ratio (ION/IOFF) by choosing the appropriate HJ positions relative to the source has been investigated [37]. Another type of HJ TFET is based on a partially unzipped CNT, where a semimetallic CNT is connected to semiconducting GNRs. This results in high-speed devices with low energy dissipation [38], [39]. These investigations demonstrated that an HJ structure is useful in improving the performance of TFETs, owing to the modulated potential profile it creates, which enhances the band-to-band (BTB) tunneling rate across the source–channel interface during the ON-state. Additionally, an HJ structure provides a more abrupt switching point while maintaining a relatively low IOFF. However, the detailed device physics of the GNR HJ TFET with different EG materials at the HJ region, and the difference between semiconducting and semimetallic HJ regions has not been systematically investigated. Toward this end, we investigate the transfer characteristics of GNR TFETs with heterogeneous semiconducting and semimetallic GNRs with appropriate ribbon widths (WHJ). For the semiconducting case, the effect of different HJ lengths (LHJ) is also investigated. In addition, the influence of gate coverage (GC) over the HJ region on the device performance of GNR TFETs is explored. We demonstrate that the HJ region forms a quantum-well structure at the source–channel interface, and the resultant quantized state (QS) enhances the BTB tunneling currents. Variation in either WHJ or LHJ changes the energy level of the QS, and hence the I–V characteristics of GNR HJ TFETs. Furthermore, we observe that BTB tunneling occurs at the gate edge, and the placement of the gate edge by adjusting the different GC over the HJ region has a great effect on the I–V characteristics of the GNR HJ TFETs. We clarify the physical mechanism in the HJ TFET structures with semiconducting and semimetallic HJ regions, and our results highlight the design considerations required, in terms of geometrical parameters and gate placement, to optimize the performance of GNR HJ TFETs, and these results can be used as general design guidelines for HJ TFETs. |