Space charge-limited current transport in thin films of alkyl-functionalized silicon nanocrystals

Pfaehler, Simon; Angi, Arzu; Chryssikos, Domenikos; Cattani-Scholz, Anna; Rieger, Bernhard und Tornow, Marc (2019): Space charge-limited current transport in thin films of alkyl-functionalized silicon nanocrystals. In: Nanotechnology, Vol. 30, No. 39, 395201

Abstract

We describe the fabrication and electrical characterization of all-silicon electrode devices to study the electronic properties of thin films of silicon nanocrystals (SiNCs). Planar, highly doped Si electrodes with contact separation of 200 nm were fabricated from silicon-on-insulator substrates, by combination of electron beam lithography and reactive ion etching. The gaps between the electrodes of height 110 nm were filled with thin-films of hexyl functionalized SiNCs (diameter 3 nm) from colloidal dispersions, via a pressure-transducing PDMS (polydimethylsiloxane) membrane. This novel approach allowed the formation of homogeneous SiNC films with precise control of their thickness in the range of 15-90 nm, practically without any voids or cracks. The measured conductance of the highly resistive SiNC films at high bias voltages up to 60 V scaled approximately linearly with gap width (5-50 pm) and gap filling height, with little device-to-device variance. We attribute the observed, pronounced hysteretic current-voltage (I-V) characteristics to space-charge-limited current transport, which-after about twenty cycles-eventually blocks the current almost completely. We propose our all-silicon device scheme and gap filling methodology as a platform to investigate charge transport in novel hybrid materials at the nanoscale, in particular in the high resistivity regime.

• Item Type: Journal article
• Faculties: Physics
• Research Centers: Center for NanoScience (CENS)
• Subjects: 500 Science > 530 Physics; 500 Science > 500 Science
• ISSN: 0957-4484
• Language: English