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This paper investigates the low-frequency noise properties of multilayer WSe2 field effect transistors (FETs) in subthreshold, linear, and saturation regime. The measured noise power spectral density of drain current (SID) shows that the low-frequency noise in multilayer WSe2 FET fits well to a 1/fγ power law with γ ~ 1 in the frequency range of 10Hz-200Hz. From the dependence of SID on the drain current, carrier mobility fluctuation is considered as a dominant low frequency noise mechanism from all operation regimes in multilayer WSe2 FET. Extracted Hooge's parameter in this study is within the value of 0.12, comparable to those of the transition metal dichalcogenide FETs in recent reports. [ABSTRACT FROM AUTHOR]

This study examined the relationship between the mobility and bias stability of pentacene-based organic field-effect transistors (OFETs) regarding a self-assembled monolayer (SAM) treatment. For this systematic study, four types of silazane-based SAMs with different alkyl chain lengths in the range of 1-8 were used. Silazane-based SAMs have an advantage of processability due to the mild reaction conditions. The mobility was increased from 0.29 without SAM to 0.46, 0.61, 0.65, and 0.84 cm²/V s after the SAM-treatment with an alkyl chain length of 1, 3, 4, and 8, respectively. On the other hand, inverse proportional relationship was observed between the bias stability and SAM alkyl chain length. Under high gate bias stress (equivalent to electric field of 3 MV/cm) for 2 h, the threshold voltage shift of the OFET was decreased from 12.19V without SAM to 5.69V with a short SAM-treatment (alkyl chain length of 1) and 7.14V with a long SAM-treatment (alkyl chain length of 8). This is the significant finding that there was a tradeoff relationship between the mobility and bias stability of OFETs concerning the SAM alkyl chain length. To overcome this tradeoff, a method for surface engineering using two-step SAM-treatment was introduced. By treating long SAM and short SAM in sequence, both the high mobility and good bias stability were achieved. With two-step SAM-treatment, the OFET showed high mobility as a long SAM-treated OFET and good bias stability as a short SAM-treated OFET. [ABSTRACT FROM AUTHOR]