Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Condensed Matter Physics

2002

Physics

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Calculations Of Surface Effects On Phonon Modes And Raman Intensities Of Ge Quantum Dots, Shang-Fen Ren, Wei Cheng Nov 2002

Calculations Of Surface Effects On Phonon Modes And Raman Intensities Of Ge Quantum Dots, Shang-Fen Ren, Wei Cheng

Faculty publications – Physics

Phonon modes and Raman intensities of Ge quantum dots (QDs) with two different types of surfaces, a free standing surface or a fixed surface, in a size range from five atoms to 7 nm in diameter, are calculated by using a microscopic valence force field model. The results are compared, and the effects of surfaces on phonon properties of QDs are investigated. It is found that phonon modes and Raman intensities of QDs with these two different types of surfaces have obvious differences which clearly reveal the effects of the surfaces of QDs. The calculated results agree with existing experimental …


Highly Anisotropic Crystal Growth And Thermoelectric Properties Of K2bi8_Xsbxse13 Solid Solutions: Band Gap Anomaly At Low X, Jeffrey S. Dyck, Theodora Kyratsi, Wei Chan, Duck-Young Chung, Ctirad Uher, Konstantinos Paraskevopoulos, Mercouri Kanatzidis Jul 2002

Highly Anisotropic Crystal Growth And Thermoelectric Properties Of K2bi8_Xsbxse13 Solid Solutions: Band Gap Anomaly At Low X, Jeffrey S. Dyck, Theodora Kyratsi, Wei Chan, Duck-Young Chung, Ctirad Uher, Konstantinos Paraskevopoulos, Mercouri Kanatzidis

Jeffrey Dyck

The thermoelectric properties of solid solutions of the type B -K2Bi8_xSbxSe13 (0


Calculations On The Size Effects Of Raman Intensities Of Silicon Quantum Dots, Wei Cheng, Shang-Fen Ren May 2002

Calculations On The Size Effects Of Raman Intensities Of Silicon Quantum Dots, Wei Cheng, Shang-Fen Ren

Faculty publications – Physics

Raman intensities of Si quantum dots (QD's) with up to 11489 atoms (about 7.6 nm in diameter) for different scattering configurations are calculated. First, phonon modes in these QD's, including all vibration frequencies and vibration amplitudes, are calculated directly from the lattice-dynamic matrix by using a microscopic valence force field model combined with the group theory. Then the Raman intensities of these quantum dots are calculated by using a bond-polarizability approximation. The size effects of the Raman intensity in these QD's are discussed in detail based on these calculations. The calculations are compared with the available experimental observations. We are …


Thermoelectric Properties Of The N-Type Filled Skutterudite Ba0.3co4sb12 Doped With Ni, Jeffrey Dyck, Wei Chen, Ctirad Uher, Lidong Chen, Xinfeng Tang, Toshio Hirai Mar 2002

Thermoelectric Properties Of The N-Type Filled Skutterudite Ba0.3co4sb12 Doped With Ni, Jeffrey Dyck, Wei Chen, Ctirad Uher, Lidong Chen, Xinfeng Tang, Toshio Hirai

Jeffrey Dyck

Synthesis and electrical and thermal transport properties are reported for several filled skutterudite compounds doped with Ni: Ba0.3NixCo4_xSb12 with 0