Two-Terminal Molecular Memories from Solution-Deposited C60 Films in Vertical Silicon Nanogaps

We demonstrate here two-terminal, charge-based memory from C-60 films inside vertical 7 nm silicon nanogap devices. This testbed structure eliminated the possibility of metal migration in the nanostructure because the two electrodes are made solely of silicon; hence, the often troublesome and confusing possibility of filamentary metal formation is obviated. Saturated solutions of C-60 in toluene, mesitylene, and 1-methylnaphthalene were each used to deposit these films at elevated temperatures. Electrical I-V measurements reveal a high yield (67%) of devices demonstrating bipolar, switchable hysteresis from both the mesitylene- and 1-methylnaphthalene-deposited devices, while the toluene-grafted devices display no such behavior. Pulse-based memory measurements of switching devices indicate high ON/OFF ratios (maximum similar to 1500), good stability (>100 cycles without device degradation) for molecular devices, and low operating currents (similar to 10(-11) A) in room temperature testing.