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We investigate the channel length dependence of the electrical characteristics of chemical vapor transport (CVT)-grown MoS 2 nanoribbon (NR) Schottky barrier field-effect transistors to provide insights into the transport properties of such nanostructures. The MoS 2 NRs form spontaneously during the CVT growth, without the application of etching. Back gated transmission line measurement FETs were fabricated on a 45 μ m-long NR with channel lengths ranging between 200 nm and 3 μ m. Contact and sheet resistances were extracted from the electrical measurements and their back-gate bias dependence was analyzed. Numerical modeling based on a virtual probe approach combined with the Landauer formalism shows excellent agreement with the measurements. The model enables a quantitative extraction of the intrinsic FET properties, e.g., mean-free-path and electron mobility, and their dependence on carrier density and investigation of plausible trap distributions. A record electron mobility for a MoS 2 NR channel of ∼ 81 cm 2 / V s was achieved.We investigate the channel length dependence of the electrical characteristics of chemical vapor transport (CVT)-grown MoS 2 nanoribbon (NR) Schottky barrier field-effect transistors to provide insights into the transport properties of such nanostructures. The MoS 2 NRs form spontaneously during the CVT growth, without the application of etching. Back gated transmission line measurement FETs were fabricated on a 45 μ m-long NR with channel lengths ranging between 200 nm and 3 μ m. Contact and sheet resistances were extracted from the electrical measurements and their back-gate bias dependence was analyzed. Numerical modeling based on a virtual probe approach combined with the Landauer formalism shows excellent agreement with the measurements. The model enables a quantitative extraction of the intrinsic FET properties, e.g., mean-free-path and electron mobility, and their dependence on carrier density and investigation of plausible trap distributions. A record electron mobility for a MoS 2... more...

The temperature (both measurement temperature and annealing temperature) and doping dependence of specific contact resistivity of Ti/Au/Pd/Au multilayer ohmic contact have been studied. The metallization for the contact involves the deposition of the composite metal layer Ti/Au/Pd/Au (200 A/600 A/400 A/500 A) on n-GaN. When the contacts were annealed at 800 °C for 30 s in air it was observed that the contact resistivity decreases with increasing doping concentration of the n-GaN, but increases with increasing measurement temperature of the contact. Within the framework of the transmission line measurement method, the specific contact resistivity for doping ND=6×1017 cm−3 was ρS=1.0×10−4 Ω cm2, and for doping ND=1020 cm−3 was ρS=2.38×10−9 Ω cm2. The resistivity ρS=1.0×10−4 Ω cm2 for ND=6×1017 cm−3 decreased to ρS≈8×10−7 Ω cm2 after a second annealing. Thus annealing, some times more than once, appears to play an important role in shaping the best value of the resistivity. The physical cause underlying the ... more...

Electrical contacts of Ni, NiSi, Cu, Au, Al, and Ti electrodes to an n-type nanocrystalline diamond film are studied at temperatures between room temperature and 500 °C in a vacuum by the transmission line measurement. Direct current-voltage characteristics measured between pairs of electrodes on the film show almost straight lines, typical of ohmic contacts, for all kinds of electrode materials. The measured series resistance is divided into resistance of the film, resistance of the electrode, and the contact resistance between the electrode and film. The Ni electrode has the lowest contact resistance, which decreases from about 380 to 200 mΩ cm2 with temperature. The contact resistance accounts for a large portion of the total resistance at low temperatures. The results confirm that the contact resistance has a close relation with the work function of electrodes such that the larger the work function, the lower the contact resistance. more...

The Pd‐In‐Ge nonspiking Ohmic contact to n‐GaAs has been investigated using the transmission line, the Kelvin, and the Cox and Strack structures. It has been found that a layered structure of Pd/In/Pd/n‐GaAs with 10–20 A of Ge imbedded in the Pd layer adjacent to the GaAs can lead to a hybrid contact. When the Ohmic formation temperature is above 550 °C, a layer of InxGa1−xAs doped with Ge is formed between the GaAs structure and the metallization. When the Ohmic formation temperature is below 550 °C, a regrown layer of GaAs also doped with Ge is formed at the metallization/GaAs interface. The contact resistivity of 2–3×10−7 Ω cm2 for this contact structure is nearly independent of the contact area from 900 to 0.2 μm2. Low‐temperature Ohmic characteristics and thermal stability are also examined. more...