Aluminium oxide prepared by UV/ozone exposure for low-voltage organic thin-film transistors

Abstract

We have developed a gate dielectric for low-voltage organic thin-film transistors based on an inorganic/organic bi-layer with a total thickness of up to ~ 20 nm. The inorganic layer is aluminium oxide formed by UV/ozone treatment of aluminium layers. The organic layer is 1-octylphosphonic acid. The preparation of aluminium oxide was studied with respect to the threshold voltage of p-channel thin-film transistors based on thermally evaporated pentacene. The results demonstrate that the threshold voltage decreases with increasing UV/ozone exposure time. The threshold voltage varies by 0.7 V and the gate-source leakage current by a factor of 10 as a function of aluminium oxide preparation. The electrical breakdown field of the bi-layer gate dielectric is at least 5 MV/cm for all AlOx preparation conditions

Dry growth of n-octylphosphonic acid monolayer for low-voltage organic thin-film transistors

“…Properties of bare AlO x and AlO x functionalized with n-octylphosphonic acid The thickness of the AlO x formed by UV/ozone oxidation is in agreement with our previous experiments [30]. C 8 PA thickness reaches value of about 1.1 nm after 90-minute desorption time.…”

“…To prevent the contamination of the oxidizing surface, UVOCS UV/ozone cleaner was enclosed under a Hepa filter. AlO x preparation by UV/ozone oxidation of thermally evaporated aluminium has been reported elsewhere [30]. Approximately 10-nm-thick (9 monolayers) C 8 PA layer was thermally evaporated on top of AlO x at room temperature.…”

Ozone oxidation methods for aluminum oxide formation: Application to low-voltage organic transistors

“…Prompted by our previous results achieved with UV/ozone oxidation of aluminum in the ambient air [16], this paper studies four different ozone oxidation methods that were applied to thermally evaporated aluminum layers. The produced oxide layers were implemented as gate dielectrics in OTFTs.…”

Structural changes in vapour-assembled n-octylphosphonic acid monolayer with post-deposition annealing: Correlation with bias-induced transistor instability

“…For FTIR, a blanket layer of aluminium was thermally evaporated and UV/ozone oxidation was used to form thin AlO x [11] with low surface roughness of ~0.48 nm [8]. C 8 PA was thermally evaporated on top of AlO x and subsequently heated to 160C for 25, 90 and 210 minutes.…”