@article{1206, keywords = {Thermal conductivity, Thermoelectric effects (semiconductors/insulators) [A7220P], Electrical conductivity of II-VI and III-V semiconductors [A7280E], electrical resistivity, Gallium, Hot pressing, II-VI and III-V semiconductors [B2520D], II-VI semiconductors, Low-field transport and mobility, Mechanical alloying, milled powders, n-type ZnO, Nonelectronic thermal conduction and heat-pulse propagation in nonmetallic solids [A6670], piezoresistance (semiconductors/insulators) [A7220F], Powder techniques, compaction and sintering [A8120E], Seebeck coefficient, Seebeck effect, Thermal diffusivity, thermoelectric figure of merit, Thermoelectric power, Zinc compounds}, author = {B. Cook and J. Harringa and Cronin Vining}, title = {Electrical properties of Ga and ZnS doped ZnO prepared by mechanical alloying}, abstract = {

A series of n-type ZnO alloys doped with Ga and ZnS were prepared by mechanical alloying. Densities of 95% to 98% of theoretical density were achieved by hot pressing the milled powders at 1000 and 1200 degrees C, respectively. The electrical resistivity and Seebeck coefficient of alloys containing 0.25-3.0 at.% Ga were characterized between 22 and 1000 degrees C. The magnitude of the resistivity and Seebeck coefficient at 22 degrees C ranged from 0.2 m Omega cm and -25 mu V/ degrees C for the most heavily doped specimen to 1.1 m Omega cm and -70 mu V/ degrees C for the lightly doped material. The alloys exhibit a positive temperature coefficient of resistivity and Seebeck coefficient with a nearly constant slope over the temperature range studied. Thermal diffusivity measurements on a specimen containing 1.0 at.% Ga were performed over the same temperature range. The thermal conductivity appears to follow a T/sup -1/ dependence, decreasing from 180 mW/cm degrees C at 22 degrees C to 82 mW/cm degrees C at 1000 degrees C. An estimate of the maximum dimensionless thermoelectric figure of merit, ZT, in this system at 1000 degrees C gives a value of 0.26, a factor of three to four less than current state-of-the-art materials such as Si-Ge. A significant reduction in thermal conductivity would be required to make these alloys competitive with existing thermoelectric power generation materials. (9 References).

}, year = {1998}, journal = {Journal of Applied Physics}, volume = {83}, pages = {61, 5858+}, month = {1998///}, url = {http://cvining.com/system/files/articles/vining/Cook-JAP-1998.pdf}, doi = {10.1063/1.367445}, language = {eng}, }