Towards Vacuum-Less Operation of Nanoscale Vacuum Channel Transistors

Electron transmission through suspended graphene membranes measured with a low-voltage gated Si field emitter array

“…In addition, a non-pristine vacuum can also lead to the generation of energetic ions that erode the emitter tips, rendering the tips blunt and deteriorating electrical performance [10]. Operation in poor vacuum using a graphene-encapsulated field emitter device at voltages less than 50 V was demonstrated in our previous work, which showed promise for poor vacuum electron transport [11].…”

“…Au/Ti (50/5 nm) was deposited on both sides of the grids by electron beam evaporation prior to graphene transfer. This step was carried out to avoid the charging of the grid as observed in our previous work [16]. The PMMA/Gr stack was "fished" using the grid substrate, which was then allowed to dry at an angle in a convection oven at 60 • C for at least 4 hrs.…”

“…The fabrication process is detailed in previous reports [11,19]. Current-voltage (I-V ) characteristics of fabricated FEAs in UHV (< 2 × 10 −9 Torr) were first measured as a three terminal device, using three source-measurement units (SMUs), to obtain a baseline of the electrical performance.…”

“…Si field emitter array Gate-Emitter Voltage, Using a conductive membrane was essential, as we found in our previous work [16] that Table 1. Extracted maximum I A and FN slopes for different grid types biased at 0 V and 50 V, compared with the case without the grid.…”

“…A, with graphene and grid A, without grid and without graphene The inclusion of the torn graphene probability has not been accounted for in (3); however, since it is only in the range of 5%-10% for fully torn-graphene, it would not affect the γ significantly. Using a conductive membrane was essential, as we found in our previous work [16] that without the presence of the conductive layer of Au/Ti, a maximum γ of only 0.19 using a 5L graphene membrane at V GE ≈ 42 V was measured. This was lower than the case of 0L membrane (grid only), where γ ∼ 0.45 at V Grid = 0 V was achieved [16].…”