Details

Autor(en) / Beteiligte

• Liu, Jun
• Miao, Mengmeng
• Jiang, Keren
• Khan, Faheem
• Goswami, Ankur
• McGee, Ryan
• Li, Zhi
• Nguyen, Lan
• Hu, Zhiyu
• Lee, Jungchul
• Cadien, Ken
• Thundat, Thomas

Titel

Sustained electron tunneling at unbiased metal-insulator-semiconductor triboelectric contacts

Ist Teil von

• Nano energy, 2018-06, Vol.48, p.320-326

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2018

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Generating sufficient current density for powering electronic devices remains as one of the critical challenges of mechanical energy harvesting techniques based on piezo and triboelectricity, mainly due to the high impedance of the insulating material systems. Here we report on producing sustainable tunneling current using an unbiased, triboelectrically charged metal-insulator-semiconductor (MIS) point contact system, consisting of p-type silicon, silicon oxide and a metal tip. The native thin oxide (~ 1.6 nm) on the silicon surface provides a natural pathway for quantum mechanical tunneling of the triboelectrically generated electrons into the silicon substrate. Lateral back and forth sliding motion of the tip, irrespective of the direction of motion, generates a constant direct current (d.c.) with very high current density. The measured current shows an exponential decay with the thickness of oxide layer deposited with atomic layer deposition (ALD), confirming the quantum mechanical tunneling mechanism. It is proposed that the contact potential difference enhanced by triboelectric charging provides potential difference between metal point contact and the substrate. With single metallic micro probe sliding on a moderately doped p-type silicon, an open circuit voltage (Voc) of 300–400 mV and a short-circuit direct current (Isc) of 3–5 μA (a corresponding high current density, J, in the order of 1–10 A/m2) have been observed. It is predicted from conductive-atomic force microscopy (C-AFM) experiment that the theoretical J can be as high as 104 A/m2. This new concept has the potential as a green energy harvesting technique where a broad range of material candidates and device configurations could be used. [Display omitted] •Quantum mechanical tunneling at triboelectrically charged interface through ultrathin oxide layer is demonstrated.•Tribo-tunneling is found to be a universal phenomenon in MIS frictional contact system.•High current density J of 5 A/m2 is experimentally measured in doped silicon materials at macroscale.•Ultrahigh C-AFM J of 104 A/m2 is observed due to the nano-size probe-induced high electric field.•This method can be used as cost-effective triboelectric DC current generator, due to easily available silicon wafers with native oxide.