[ODCAD] UCLA's organic memory-mechanism

A UCLA material scientist, Yang Yang discovered a simple organic memory device. A patent [1] has been filed to protect this IP because it has great potential to be applicable to the industry.

This device manufacture and operation has been described in previous topic "UCLA-a Simple organic memory". The latest result from Yang Yang's work [2] shows that the "on" state is not filament. This is because the "ON" state conductivity is proportional to the cross section area of device. The on conductivity is an increase function of temperature. This indicate that the on state is not "metal" state.

AFM image shows that the middle Al layer in the device (Al/Organic/Al/Organic/Al) has b nano crystal structure. X ray spectroscopy demonstrated that this nano crystal may be in form of oxide. The oxide may be formed due to exposed to air. It would be interested to see what behavior the device has if the middle Al is in metal form.
UV-visible absorption spectra can see that the middle layer Al quality gives significant difference in terms of its structure. Al deposited at slow rate can give high yield of the device.

These observations indicate that the Al oxide in the middle layer function as charge carrier trap. After switched on, the injected charge carrier are trapped. Therefore, the conductivity has been significantly increased.

It would be more convincing if proper energy level is used for explaining the trap mechanism. The Al is in nano cluster form. The bulk Al energy level can not be applied here. Possibly there are quantum wells produced by the crystal cluster. It would be a great research topic for scientist.


1. US pending patent US 01/17206 (2001)
2. L. Ma, S., Pyo, J. Ouyang, Q. Xu, Y. Yang, Appl. Phys. Lett., 82, 1419 (2003)
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