High-Output-Power Densities from MBE-grown n- and p-Type PbTeSe-based Thermoelectrics via Improved Contact Metallization
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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Electrical power densities of up to 33 Wsq cm and up to 12 Wsq cm were obtained for n-type and p-type PbTeSe-based stand-alone thermoelectric devices, respectively, at modest temperature gradients of 200 deg C Tcold25 deg C. These large power densities were enabled by greatly improving electrical contact resistivities in the thermoelectric devices. Robust electrical contacts with contact resistivities as low as 3.9x10exp 6 ohm-sq cm and 4.0x10exp 6 ohm-sq cm for n- and p-type telluride-based-materials, respectively, were developed by investigating several metallization schemes and contact layer dopingalloy combinations, in conjunction with a novel contact application process. This process exposes heated semiconductor surfaces to an atomic hydrogen flux under high vacuum for surface cleaning oxide and carbon removal, followed immediately by an in-situ electron-beam evaporation of the metal layers.
- Electrical and Electronic Equipment
- Solid State Physics