Detection of Charge Storage on Molecular Thin Films of Tris(8-hydroxyquinoline) Aluminum (Alq3) by Kelvin Force Microscopy: A Candidate System for High Storage Capacity Memory Cells

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• 作者：Sarah Paydavosi ; Katherine E. Aidala ; Patrick R. Brown ; Pouya Hashemi ; Geoffrey J. Supran ; Timothy P. Osedach ; Judy L. Hoyt ; Vladimir Bulovi膰
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：March 14, 2012
• 年：2012
• 卷：12
• 期：3
• 页码：1260-1264
• 全文大小：359K
• 年卷期：v.12,no.3(March 14, 2012)
• ISSN：1530-6992

文摘

Retention and diffusion of charge in tris(8-hydroxyquinoline) aluminum (Alq₃) molecular thin films are investigated by injecting electrons and holes via a biased conductive atomic force microscopy tip into the Alq₃ films. After the charge injection, Kelvin force microscopy measurements reveal minimal changes with time in the spatial extent of the trapped charge domains within Alq₃ films, even for high hole and electron densities of >10¹² cm^鈥?. We show that this finding is consistent with the very low mobility of charge carriers in Alq₃ thin films (<10^鈥? cm²/(Vs)) and that it can benefit from the use of Alq₃ films as nanosegmented floating gates in flash memory cells. Memory capacitors using Alq₃ molecules as the floating gate are fabricated and measured, showing durability over more than 10⁴ program/erase cycles and the hysteresis window of up to 7.8 V, corresponding to stored charge densities as high as 5.4 脳 10¹³ cm^鈥?. These results demonstrate the potential for use of molecular films in high storage capacity nonvolatile memory cells.

Keywords:

Flash memory; charge storage; molecules; organic; nonvolatile; Kelvin force microscopy; Alq₃; tris(8-hydroxyquinoline) aluminum