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Electrical spin injection and detection in molybdenum disulfide multilayer channel

View Article: PubMed Central - PubMed

ABSTRACT

Molybdenum disulfide has recently emerged as a promising two-dimensional semiconducting material for nano-electronic, opto-electronic and spintronic applications. However, the demonstration of an electron spin transport through a semiconducting MoS2 channel remains challenging. Here we show the evidence of the electrical spin injection and detection in the conduction band of a multilayer MoS2 semiconducting channel using a two-terminal spin-valve configuration geometry. A magnetoresistance around 1% has been observed through a 450 nm long, 6 monolayer thick MoS2 channel with a Co/MgO tunnelling spin injector and detector. It is found that keeping a good balance between the interface resistance and channel resistance is mandatory for the observation of the two-terminal magnetoresistance. Moreover, the electron spin-relaxation is found to be greatly suppressed in the multilayer MoS2 channel with an in-plane spin polarization. The long spin diffusion length (approximately ∼235 nm) could open a new avenue for spintronic applications using multilayer transition metal dichalcogenides.

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Drain-source bias and temperature-dependent MR characterization of the device.(a) Vds dependence of MR measured at 23 K with Vg=+20 V. (b) The total resistance (R) of the device versus Vds. The area with orange colour indicates the Vds range where the total resistance is dominated by the contact resistance. (c) Temperature dependence of MR measured with Vg=+20 V and Vds=−0.1 V. (d) Temperature dependence of the total resistance (R) with different Vds and the MoS2 channel mobility μ (Vg=+20 V, Vds=−1 V). The error bars in a,c have been calculated by taking account of the signal noise and the contribution of leakage current.
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f4: Drain-source bias and temperature-dependent MR characterization of the device.(a) Vds dependence of MR measured at 23 K with Vg=+20 V. (b) The total resistance (R) of the device versus Vds. The area with orange colour indicates the Vds range where the total resistance is dominated by the contact resistance. (c) Temperature dependence of MR measured with Vg=+20 V and Vds=−0.1 V. (d) Temperature dependence of the total resistance (R) with different Vds and the MoS2 channel mobility μ (Vg=+20 V, Vds=−1 V). The error bars in a,c have been calculated by taking account of the signal noise and the contribution of leakage current.

Mentions: The bias dependence of MR measured with Vg=+20 V at 12 K is displayed in Fig. 4a. It is found that the MR ratio decreases with the increase of bias /Vds/. When /Vds/ is larger than 0.15 V, MR almost disappears. We note that the total resistance also decreases rapidly with the increase of /Vds/ (Fig. 4b), especially in the range /Vds/<0.15 V where RC is considered to be dominant as mentioned above. This indicates that the observation of MR could be related to the large contact resistance introduced to overcome the impedance mismatch at Co/MgO/MoS2 interface. In Fig. 4c, we display the temperature (T) dependence of MR acquired with Vg=+20 V and Vds=−0.1 V: the MR rapidly decreases with T. When T>60 K, MR almost disappears. This thermal behaviour could be also associated to the variation of RC versus T if one assumes a constant spin polarization at Co/MgO interface30. In Fig. 4d, the total resistance as a function of T is plotted for different Vds conditions. It appears obviously that the resistance at Vds=−0.04 V (RC dominant) decreases rapidly when T>60K, while the resistance with Vds=−1 V (RMS+2RMgO) decreases more slowly with T. Therefore, a strong correlation between the contact resistance and MR is also revealed from the temperature dependence of MR. In Fig. 4d, we also show the temperature variation of mobility derived at Vg=+20 V and Vds=−1 V. It is noted that the mobility of MoS2 channel shows a slight increase with temperature up to 200 K, which could be due to the scattering from the charged impurities28. Supplementary data for MR measurements (temperature, bias and back-gate dependence) can be found in Supplementary Note 6.


Electrical spin injection and detection in molybdenum disulfide multilayer channel
Drain-source bias and temperature-dependent MR characterization of the device.(a) Vds dependence of MR measured at 23 K with Vg=+20 V. (b) The total resistance (R) of the device versus Vds. The area with orange colour indicates the Vds range where the total resistance is dominated by the contact resistance. (c) Temperature dependence of MR measured with Vg=+20 V and Vds=−0.1 V. (d) Temperature dependence of the total resistance (R) with different Vds and the MoS2 channel mobility μ (Vg=+20 V, Vds=−1 V). The error bars in a,c have been calculated by taking account of the signal noise and the contribution of leakage current.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5385572&req=5

f4: Drain-source bias and temperature-dependent MR characterization of the device.(a) Vds dependence of MR measured at 23 K with Vg=+20 V. (b) The total resistance (R) of the device versus Vds. The area with orange colour indicates the Vds range where the total resistance is dominated by the contact resistance. (c) Temperature dependence of MR measured with Vg=+20 V and Vds=−0.1 V. (d) Temperature dependence of the total resistance (R) with different Vds and the MoS2 channel mobility μ (Vg=+20 V, Vds=−1 V). The error bars in a,c have been calculated by taking account of the signal noise and the contribution of leakage current.
Mentions: The bias dependence of MR measured with Vg=+20 V at 12 K is displayed in Fig. 4a. It is found that the MR ratio decreases with the increase of bias /Vds/. When /Vds/ is larger than 0.15 V, MR almost disappears. We note that the total resistance also decreases rapidly with the increase of /Vds/ (Fig. 4b), especially in the range /Vds/<0.15 V where RC is considered to be dominant as mentioned above. This indicates that the observation of MR could be related to the large contact resistance introduced to overcome the impedance mismatch at Co/MgO/MoS2 interface. In Fig. 4c, we display the temperature (T) dependence of MR acquired with Vg=+20 V and Vds=−0.1 V: the MR rapidly decreases with T. When T>60 K, MR almost disappears. This thermal behaviour could be also associated to the variation of RC versus T if one assumes a constant spin polarization at Co/MgO interface30. In Fig. 4d, the total resistance as a function of T is plotted for different Vds conditions. It appears obviously that the resistance at Vds=−0.04 V (RC dominant) decreases rapidly when T>60K, while the resistance with Vds=−1 V (RMS+2RMgO) decreases more slowly with T. Therefore, a strong correlation between the contact resistance and MR is also revealed from the temperature dependence of MR. In Fig. 4d, we also show the temperature variation of mobility derived at Vg=+20 V and Vds=−1 V. It is noted that the mobility of MoS2 channel shows a slight increase with temperature up to 200 K, which could be due to the scattering from the charged impurities28. Supplementary data for MR measurements (temperature, bias and back-gate dependence) can be found in Supplementary Note 6.

View Article: PubMed Central - PubMed

ABSTRACT

Molybdenum disulfide has recently emerged as a promising two-dimensional semiconducting material for nano-electronic, opto-electronic and spintronic applications. However, the demonstration of an electron spin transport through a semiconducting MoS2 channel remains challenging. Here we show the evidence of the electrical spin injection and detection in the conduction band of a multilayer MoS2 semiconducting channel using a two-terminal spin-valve configuration geometry. A magnetoresistance around 1% has been observed through a 450&thinsp;nm long, 6 monolayer thick MoS2 channel with a Co/MgO tunnelling spin injector and detector. It is found that keeping a good balance between the interface resistance and channel resistance is mandatory for the observation of the two-terminal magnetoresistance. Moreover, the electron spin-relaxation is found to be greatly suppressed in the multilayer MoS2 channel with an in-plane spin polarization. The long spin diffusion length (approximately &sim;235&thinsp;nm) could open a new avenue for spintronic applications using multilayer transition metal dichalcogenides.

No MeSH data available.


Related in: MedlinePlus