Thermal and Electrical Properties of Heavily Doped Ge-Si Alloys up to 1300°K

Abstract

The thermal resistivity, Seebeck coefficient, electrical resistivity, and Hall mobility of Ge-Si alloys have been measured throughout the Ge-Si alloy system as functions of impurity concentration in the range 2×1018−4×1020cm−3, and of temperature in the range 300°–1300°K. A qualitative interpretation of these properties is given. For power conversion, boron and phosphorus were found to be useful p-type and n-type impurities, respectively, because of their high solid solubilities. At 1200°K, the maximum values of the dimensionless figure of merit zT were 0.8 for p-type Ge0.15-Si0.85 alloy doped to 2.1×1020cm−3 holes, and 1.0 for n-type Ge0.15-Si0.85 alloy doped to 2.7×1020cm−3 electrons. The maximum over-all efficiency of a stable generator operating between 300°–1200°K, using the best p-type and n-type materials was computed to be 10%.

Cross-plane thermal conductivity reduction of vertically uncorrelated Ge∕Si quantum dot superlattices

“…The equivalent Ge fraction of the QDSL is estimated to be 3%. The thermal conductivity of an undoped Si 0.97 Ge 0.03 alloy at 300 K is about 17 W / mK, 19 slightly above the value measured for the correlated sample, 14.5 W / mK. This value can be qualitatively compared to results of Refs.…”

Lattice thermal conductivity of group-IV and III–V semiconductor alloys

“…͑1͒ and ͑2͒ without taking into account the alloydisorder contribution ͑C C-Si =0 cm K/W͒, while the dashed lines are calculated with assuming C C-Si =15 cm K/W. 21 The open circles represent the experimental data of the end point materials listed in Table I. The solid lines are obtained from Eqs.…”

“…16 and 20͒ have been reported. Systematic work on thermal conductivity of Si x Ge 1−x binary alloy was performed by Dismukes et al 21 We plot in Table I͒. 14 The solid lines are calculated from Eqs.…”

Role of Nanoscale Precipitates for Enhancement of Thermoelectric Properties of Heavily P-Doped Si-Ge Alloys

“…The κ lat of Si can be greatly decreased by forming a solid solution with germanium (Ge), and the best composition, Si 100-x Ge x (x = 20~30), shows the highest zT value, of approximately 0.7-0.8. [7][8][9][10] However, issues such as the still low zT and the high cost of Ge have limited the industrial applications of these materials. Recently, it has been experimentally proven that nanostructring also reduces the κ lat and hence greatly improves the zT of various materials, [11][12][13][14][15] including bulk Si and Si-Ge alloys.…”