AlGaN/GaN Three-Terminal Junction Devices for Rectification and Transistor Applications on 3C-SiC/Si Pseudosubstrates

Graphene Nanoribbons for Electronic Devices

“…[] for example, a TTJ on InP substrate showing a steady‐state rectification efficiency around 50% and voltage rectification at frequencies up to 94 GHz has been demonstrated and in Ref. [] a GaN‐based TTJ with a rectification efficiency of almost 100% has been reported. Beyond voltage rectification, AlGaAs/GaAs TTJs with FET‐like output and transfer characteristics showing excellent switch‐off have been demonstrated, TTJ logic gates have been reported , and frequency multiplication with TTJs has been realized .…”

All-Graphene Three-Terminal-Junction Field-Effect Devices as Rectifiers and Inverters

“…Charge carrier transport in a two-dimensional electron gas (2-DEG) has been widely studied for the past decades to exploit its nonlinear properties arising in the ballistic regime. − Owing to the entirely two-dimensional lattice and exceptional electronic properties, graphene has recently attracted attention as a 2-DEG material. Recent developments on chemical vapor deposition (CVD) of continuous monolayer graphene enable cost-effective synthesis, and this has resulted in increased interest also in the industry. − Graphene field-effect transistors (GFETs) are among the most studied device structures for future electronic applications due to transparency, flexibility, and high carrier mobility. − Recently, state-of-the-art GFET structures have surpassed the gigahertz limit not only on a conventional rigid substrate such as Si but even on flexible substrates. ,− However, the transistor performance as a switch or rectifier is limited due to the zero band gap in graphene.…”

“…In a TTJ, consequently, positive output is generally expected in the hole region (as a positive rectification) and negative in the electron region (as a negative rectification) . Conventional III–V semiconductor based T-branch junction (TBJ) devices show negative rectifications, as they have only electrons as charge carriers. − , Exceptionally, rectification whose sign is determined by the dimension and geometry of the junction scale has also been reported: unexpectedly the rectification is changed from negative to positive when the channel width of the TBJ is more than ∼250 nm (but no more than a few micrometers). The origin of geometry-dependent rectification has not been confirmed, but may be associated with nonidentical potentials at the contacts. , Nevertheless, the sign of rectification is predetermined by the physical device’s parameters and is not controllable during device operation.…”

“…Conventional III–V semiconductor based T-branch junction (TBJ) devices show negative rectifications, as they have only electrons as charge carriers. − , Exceptionally, rectification whose sign is determined by the dimension and geometry of the junction scale has also been reported: unexpectedly the rectification is changed from negative to positive when the channel width of the TBJ is more than ∼250 nm (but no more than a few micrometers). The origin of geometry-dependent rectification has not been confirmed, but may be associated with nonidentical potentials at the contacts. , Nevertheless, the sign of rectification is predetermined by the physical device’s parameters and is not controllable during device operation. Graphene-based devices, on the other hand, exhibit both positive and negative rectifications by the gate field control. − So far, nonlinear behaviors have been studied for rectification only in nanoscale graphene TBJs (channel width ∼50–300 nm), minimizing the scattering events in carrier transport toward the ballistic effect. − Although they are very intriguing from an academic point of view and are promising for nanoelectronics, ballistic operations are impractical for flexible and transparent application owing to the strict nanoscale size requirements.…”

“…8 At high V 0 , for example, V 0 > 1 V, the process can be understood so that the carriers associated with phonons are thermally emitted, losing their velocity during traveling, and they, consequently, can be accumulated near the anode (a positive-biased contact in the electron region and vice versa in the hole region). The accumulation yields a high resistivity, resulting in a stronger voltage drop in the channel, 8,14 enabling rectification even in the long-channel diffusive regime. This indicates that the sign of the potential shift is strongly dependent on the type of charge carriers.…”