Black phosphorus (BP) has been recently rediscovered as an elemental two-dimensional (2D) materia... more Black phosphorus (BP) has been recently rediscovered as an elemental two-dimensional (2D) material that shows promising results for next generation electronics and optoelectronics because of its intrinsically superior carrier mobility and small direct band gap. In various 2D field-effect transistors (FETs), the choice of metal contacts is vital to the device performance, and it is a major challenge to reach ultralow contact resistances for highly scaled 2D FETs. Here, we experimentally show the effect of a work function tunable metal contact on the device performance of BP FETs. Using palladium (Pd) as the contact material, we employed the reaction between Pd and H 2 to form a Pd−H alloy that effectively increased the work function of Pd and reduced the Schottky barrier height (Φ B) in a BP FET. When the Pd-contacted BP FET was exposed to 5% hydrogen concentrated Ar, the contact resistance (R c) improved between the Pd electrodes and BP from ∼7.10 to ∼1.05 Ω· mm, surpassing all previously reported contact resistances in the literature for BP FETs. Additionally, with exposure to 5% hydrogen, the transconductance of the Pd-contacted BP FET was doubled. The results shown in this study illustrate the significance of choosing the right contact material for high-performance BP FETs in order to realize the real prospect of BP in electronic applications.
Black phosphorus (BP) has been recently rediscovered as an elemental two-dimensional (2D) materia... more Black phosphorus (BP) has been recently rediscovered as an elemental two-dimensional (2D) material that shows promising results for next generation electronics and optoelectronics because of its intrinsically superior carrier mobility and small direct band gap. In various 2D field-effect transistors (FETs), the choice of metal contacts is vital to the device performance, and it is a major challenge to reach ultralow contact resistances for highly scaled 2D FETs. Here, we experimentally show the effect of a work function tunable metal contact on the device performance of BP FETs. Using palladium (Pd) as the contact material, we employed the reaction between Pd and H 2 to form a Pd−H alloy that effectively increased the work function of Pd and reduced the Schottky barrier height (Φ B) in a BP FET. When the Pd-contacted BP FET was exposed to 5% hydrogen concentrated Ar, the contact resistance (R c) improved between the Pd electrodes and BP from ∼7.10 to ∼1.05 Ω· mm, surpassing all previously reported contact resistances in the literature for BP FETs. Additionally, with exposure to 5% hydrogen, the transconductance of the Pd-contacted BP FET was doubled. The results shown in this study illustrate the significance of choosing the right contact material for high-performance BP FETs in order to realize the real prospect of BP in electronic applications.
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Papers by Zhen Li