Equation (1) demonstrates the feasibility of applying the electrochemical method to synthesize the InSb nanowires at room temperature.
To evaluate the basic electrical transport characteristics of the as-prepared InSb nanowire, a FET was fabricated. Figure 2a shows the I ds versus V ds curve of the single InSb nanowire under various V gs (gate bias) from 2 to 6 V. The I ds versus V ds curve of the InSb nanowire revealed a pronounced n-type semiconductor property, in which the current of the nanowire increases with an increasing gate bias. The n-type conductivity might have originated from the Sb vacancies in the InSb nanowires [22–24]. The Sb vacancy may derive from the surface defects, as reported in our previous work . Additionally, other semiconductor-related APO866 nmr studies described the vacancy-induced Selleck DAPT n-type conductivity in 1D nanoscale [26, 27]. The inset revealed the SEM image of the single InSb nanowire connected to Cu electrodes. Figure 2b shows that I ds is dependent on V gs at V ds as 5 V. The I ds increased when V gs increased from −7 to 11 V; in addition, the I on/I off ratio was only approximately 8.9. The channel transconductance could be deduced based on the linear region from −4 to 7 V. Correspondingly,
the electron mobility (μ) of the InSb nanowire could be estimated using the following equation : (2) where gm is the channel transconductance of FET gm = ∂ Ids / ∂ Vgs. C is the nanowire capacitance, and L is the nanowire length BCKDHA EX 527 research buy between the electrodes. The capacitance of the nanowire can be regarded as , where
is the dielectric constant of SiO2 (approximately 3.9), ϵ0 is the vacuum permittivity, h is the thickness of SiO2 (120 nm), and d is the average radius of the InSb nanowires. These equations show that the calculation of the μ is 215.25 cm2 V−1 s−1 at V ds = 5 V. The value is about two times higher than the reported value of PLD fabricated InSb nanowires . However, the value is much smaller than those of the bulk and other reported InSb nanowires [29, 30]. The possible reasons are attributed to the scattering and trapping of electrons, and high contact resistance [31, 32]. The trapping of electrons in the trap states (O2(g) + e − → O2 − (ad)) can cause electron depletion in the channel. Next, the surface roughness (due to the presence of surface defects) and impurity may cause electron scattering, leading to the limited mobility. It is still higher than other application of photodetector of oxide semiconductor materials [33–35]. This implies that it may affect the sensitivity of the photodetector. Furthermore, according to σ = nqμ, where the σ is the conductivity, n is the electron concentration, q is the charge of an electron, and μ is the mobility, the corresponding electron concentration (n e) of the InSb nanowire was estimated to be 3.6 × 1017 cm−3. Figure 2 The characteristics of the field-effect transistor based on an individual InSb nanowire.