Leveraging nanoscale field-effect transistors (FETs) in integrated circuits depends heavily on its transfer characteristics and low-frequency noise (LFN) properties. Here, we report the transfer characteristics and LFN in FETs fabricated with molybdenum disulfide (MoS2) with different layer (L) counts. 4L to 6L devices showed highest ION-IOFF ratio (≈108) whereas LFN was maximum for 1L device with normalized power spectral density (PSD) ≈1.5 × 10−5 Hz−1. For devices with L ≈ 6, PSD was minimum (≈2 × 10−8 Hz−1). Further, LFN for single and few layer devices satisfied carrier number fluctuation (CNF) model in both weak and strong accumulation regimes while thicker devices followed Hooge's mobility fluctuation model in the weak accumulation regime and CNF model in strong accumulation regime, respectively. Transfer-characteristics and LFN experimental data are explained with the help of model incorporating Thomas-Fermi charge screening and inter-layer resistance coupling.

We have studied temperature-dependent (77-300 K) electrical characteristics and low-frequency noise (LFN) in chemical vapor deposited (CVD) single-layer molybdenum disulfide (MoS2) based back-gated field-effect transistors (FETs). Electrical characterization and LFN measurements were conducted on MoS2 FETs with Al2O3 top-surface passivation. We also studied the effect of top-surface passivation etching on the electrical characteristics of the device. Significant decrease in channel current and transconductance was observed in these devices after the Al2O3 passivation etching. For passivated devices, the two-terminal resistance variation with temperature showed a good fit to the activation energy model, whereas for the etched devices the trend indicated a hopping transport mechanism. A significant increase in the normalized drain current noise power spectral density (PSD) was observed after the etching of the top passivation layer. The observed channel current noise was explained using a standard unified model incorporating carrier number fluctuation and correlated surface mobility fluctuation mechanisms. Detailed analysis of the gate-referred noise voltage PSD indicated the presence of different trapping states in passivated devices when compared to the etched devices. Etched devices showed weak temperature dependence of the channel current noise, whereas passivated devices exhibited near-linear temperature dependence.

We report detailed characterization of electrically-active deep-levels in doped Si nanowires (SiNWs) grown using catalyst-assisted vapor-liquid-solid (VLS) technique. Temperature-dependent low-frequency noise (LFN) spectroscopy was used to reveal the presence of generation-recombination related Lorentzian-type peaks along with 1/f -type noise in these NWs. In Ni-catalyzed SiNWs, the correlated LFN spectroscopy detected electrically active deep-levels with ionization energies of 0.42 eV for the n-type and 0.22 eV for the p-type SiNWs, respectively. In Au-catalyzed n- and p-type SiNWs, the energies of the deep-levels were estimated to be 0.44 and 0.38 eV, respectively. These values are in good agreement with the known ionization energies of deep-levels introduced by Ni and Au in Si. Associated trap concentrations and hole and electron capture cross sections were also estimated. This paper clearly indicated the presence of electrically active deep-levels associated with unintentional incorporation of catalyst atoms in the VLS-grown SiNWs.