Effect of Deposition Rates on Vacuum Deposited Pentacene Thin Films for Memory Device Applications

Effect of vacuum annealing on evaporated pentacene thin films for memory device applications

“…After this transition, the device remained in the same state even after turning off of the power as shown in the second voltage scan. It revealed the non volatile nature of the pentacene device and the switching was irreversible as reported earlier [10][11][12] and never returned to its initial off state even after applying a negative voltage pulse as shown in third scan. This property makes pentacene potentially suitable for a WORM memory device material.…”

“…The decrease in the performance of this device may be due to the structural and morphological changes. All these devices also showed irreversible switching making them suitable for WORM applications as previously reported [10][11][12].…”

“…For the device annealed at 373 K, the current increased suddenly from 3.88 Â 10 À11 A to 3.15 Â 10 À2 A at V T of 1.35 V with an ON/OFF ratio 10 9 , which was more than the previously reported values [10][11][12]. Here the OFF current was lower than that of non-annealed device, but ON/OFF ratio was increased compared to that of non-annealed device with a decrease in the threshold voltage.…”

“…Among the currently used organic materials, pentacene (C 22 H 14 ) is proved to be a promising candidate for solar cells [1][2][3][4][5], thin film transistors [6][7][8], photo detectors [9] and memory devices [10][11][12] due to its polycrystalline morphology, large carrier mobility, small optical band gap, long exciton diffusion length and strong absorption in the visible region of solar spectrum. Pentacene is an organic semiconductor consisting of five p-conjugated aromatic benzene rings as shown in Fig.…”

“…They compared the device with Al electrode and suggested that Fe has the advantage over Al as it lowers the switching threshold voltage. Organic electrical memory devices with a simple structure based on a single layer pentacene film embedded between Al and ITO electrodes for different deposition rates of pentacene were studied and the performance of this reliable device with a high ON/OFF current ratio was reported [12]. There are many organic materials that are being used as memory device elements that provide fast, non-volatile memory device with high density data storage, high writing/reading stability and long retention time [17][18][19][20][21][22].…”