The quadruple-level cell technology is demonstrated in an Au/Al O /HfO /TiN resistance switching memory device using the industry-standard incremental step pulse programming (ISPP) and error checking/correction (ECC) methods. With the highly optimistic properties of the tested device, such as self-compliance and gradual set-switching behaviors, the device shows 6σ reliability up to 16 states with a state current gap value of 400 nA for the total allowable programmed current range from 2 to 11 µA. It is demonstrated that the conventional ISPP/ECC can be applied to such resistance switching memory, which may greatly contribute to the commercialization of the device, especially competitively with NAND flash. A relatively minor improvement in the material and circuitry may enable even a five-bits-per-cell technology, which can hardly be imagined in NAND flash, whose state-of-the-art multiple-cell technology is only at three-level (eight states) to this day.

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Phone: þ82 42 860 7677, Fax: þ82 42 861 4151A study of substrate effect on the thermoelectric (TE) properties of Bi 2 Te 3 (BT) and Sb 2 Te 3 (ST) thin films grown by plasma-enhanced chemical vapor deposition (PECVD) was performed. Graphene substrates which have small lattice mismatch with BT and ST were used for the preparation of highly oriented BT and ST thin films. Carrier mobility of the epitaxial BT and ST films grown on the graphene substrates increased as the deposition temperature increased, which was not observed in that of SiO 2 /Si substrates. Seebeck coefficients of the as-grown BT and ST films were observed to be maintained even though carrier concentration increased in the epitaxial BT and ST films on graphene substrate. Although Seebeck coefficient was not improved, power factor of the as-grown BT and ST films was considerably enhanced due to the increase of electrical conductivity resulting from the high carrier mobility and moderate carrier concentration in the epitaxial BT and ST films.Thermoelectric (TE) energy generators have promising applications in the operation of micro-scale electric devices and systems. Many previous researches have been focused on the enhancement of the efficiency of TE materials [1][2][3][4][5][6][7][8]. The efficiency of thermoelectric materials depends on the dimensionless thermoelectric figure of merit ZT ¼ a 2 sT/k where a, T, s, and k are the Seebeck coefficient, absolute temperature, electrical conductivity, and thermal conductivity, respectively. The recent reports explained that the enhancement of ZT was mainly due to the reduction of k by nanostructure-engineering which dramatically increases phonon boundary scattering at interfaces [1,2,[5][6][7]. However, the enhancement of ZT by increasing the thermoelectric power factor (a 2 s) has been reported [9][10][11][12].Various deposition methods have been reported for preparation of highly oriented Bi 2 Te 3 (BT) and Sb 2 Te 3 (ST) thin films, such as molecular beam epitaxy (MBE), metal-organic chemical vapor deposition (MOCVD), and pulsed laser deposition (PLD) [13][14][15]. MOCVD has attracted the most amount of attention due to its low cost and high controllability for thin film growth, which make it most suitable for large-scale production. On the other hand, the plasma-enhanced chemical vapor deposition (PECVD) has an advantage of low deposition temperature with a relatively high deposition rate in comparison with conventional MOCVD process.It is well known that the electrical conductivity of BT and ST along c-plane is much higher than that of c-axis because of the layered structural characteristics of single crystalline BT and ST [16,17]. Furthermore, epitaxial BT and ST thin films are also expected to have higher power factors than that of polycrystalline. However, latticematched substrate for BT and ST has rarely been reported until now except expensive yet small-sized crystalline

Sb2Se3, a quasi-1D structured binary chalcogenide, has great potential as a solar cell light absorber owing to its anisotropic carrier transport and benign grain boundaries when the absorber layer is...

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