Thermoelectric properties of In-rich InGaN and InN/InGaN superlattices
- Walter Schottky Institut, Physik Department, TU München, 85748 Garching (Germany)
- Department of Mechanical Engineering, National University of Singapore, 117576 (Singapore)
The thermoelectric properties of n-type InGaN alloys with high In-content and InN/InGaN thin film superlattices (SL) grown by molecular beam epitaxy are investigated. Room-temperature measurements of the thermoelectric properties reveal that an increasing Ga-content in ternary InGaN alloys (0 < x(Ga) < 0.2) yields a more than 10-fold reduction in thermal conductivity (κ) without deteriorating electrical conductivity (σ), while the Seebeck coefficient (S) increases slightly due to a widening band gap compared to binary InN. Employing InN/InGaN SLs (x(Ga) = 0.1) with different periods, we demonstrate that confinement effects strongly enhance electron mobility with values as high as ∼820 cm{sup 2}/V s at an electron density n{sub e} of ∼5×10{sup 19} cm{sup −3}, leading to an exceptionally high σ of ∼5400 (Ωcm){sup −1}. Simultaneously, in very short-period SL structures S becomes decoupled from n{sub e}, κ is further reduced below the alloy limit (κ < 9 W/m-K), and the power factor increases to 2.5×10{sup −4} W/m-K{sup 2} by more than a factor of 5 as compared to In-rich InGaN alloys. These findings demonstrate that quantum confinement in group-III nitride-based superlattices facilitates improvements of thermoelectric properties over bulk-like ternary nitride alloys.
- OSTI ID:
- 22611676
- Journal Information:
- AIP Advances, Vol. 6, Issue 4; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPARATIVE EVALUATIONS
ELECTRIC CONDUCTIVITY
ELECTRON DENSITY
ELECTRON MOBILITY
ELECTRONS
GALLIUM COMPOUNDS
INDIUM NITRIDES
MOLECULAR BEAM EPITAXY
MOLECULAR BEAMS
REDUCTION
SUPERLATTICES
TEMPERATURE MEASUREMENT
TEMPERATURE RANGE 0273-0400 K
TERNARY ALLOY SYSTEMS
THERMAL CONDUCTIVITY
THERMOELECTRIC PROPERTIES
THIN FILMS