Vertical Graphene-Base Hot-Electron Transistor

Abstract

We demonstrate vertical graphene-base hot-electron transistors (GB-HETs) with a variety of structures and material parameters. Our GB-HETs exhibit a current saturation with a high current on-off ratio (>10(5)), which results from both the vertical transport of hot electrons across the ultrathin graphene base and the filtering of hot electrons through a built-in energy barrier. The influences of the materials and their thicknesses used for the tunneling and filtering barriers on the common-base current gain α are studied. The optimization of the SiO2 thickness and using HfO2 as the filtering barrier significantly improves the common-base current gain α by more than 2 orders of magnitude. The results demonstrate that GB-HETs have a great potential for high-frequency, high-speed, and high-density integrated circuits.

High Performance Amplifier Element Realization via MoS2/GaTe Heterostructures

“…Additionally, other NPN HBT‐based MoS 2 /GaTe/n‐Si heterostructures were also fabricated using the same methods provided in Section 4 of the Supporting Information, whose characteristics are not as good as ours but also shows conventional NPN BJT characteristics. Our device performance and properties are compared with other reported HBT/HET devices based on 2D materials and listed in Table 1 36, 37, 38, 39, 40, 41. The theory of HETs is different than the theory of BJT/HETs, and there is a barrier between the emitter and the base layer in HETs.…”

Resonant plasmonic terahertz detection in vertical graphene-base hot-electron transistors

“…The comparison of the GB-HETs [1][2][3][4] and InPDHBTs [51][52][53] with the GB-HETs under consideration highlights the following advantages of the latter: (i) a longer momentum relaxation time of holes τ in the GB; (ii) a higher plasma-wave velocity s that enables higher resonant plasma frequencies; (iii) a smaller capture probability of hot electrons into the GB and, consequently, larger (or even much larger) fraction of the hot electrons reaching the collector; (iv) coupling the incoming THz signal to the GB resulting in the absence of the ac current in the emitter-collector circuit and prevanting the RC effects usually hindering the high-frequency operation.…”

“…Recently, vertical hot-electron transistors (HETs) with the graphene base (GB) and the bulk emitter and collector separated from the base by the barrier layersthe hot-electron graphene-base transistors (GB-HETs) -made of SiO 2 and Al 2 O 3 were fabricated and studied [1][2][3][4]. These HETs are fairly promising devices despite their modest characteristics at the present.…”

Electrical Compact Modeling of Graphene Base Transistors

“…The 1-D numerical model of [9] solves the electrostatics of the GBT self-consistently with the calculated tunneling current and estimates the transit frequency fT. Concerning the currents, since the physical origin of the base current is still unclear and debated [7,16], a perfectly transparent graphene layer is assumed and the base current is neglected. Hence, we assume a priori that the collector current is the current due to electrons injected from the emitter and, consistently, crossing the whole device.…”