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Structure of Ge‐Based Films Exhibiting Thermoelectric Effect
Author(s) -
BeenshMarchwicka G. M.,
Prociów E.,
Mielcarek W.
Publication year - 2001
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/1521-4079(200110)36:8/10<1035::aid-crat1035>3.0.co;2-m
Subject(s) - materials science , crystallite , sputter deposition , dopant , amorphous solid , thermoelectric effect , sputtering , thin film , annealing (glass) , dopant activation , seebeck coefficient , microcrystalline , analytical chemistry (journal) , doping , optoelectronics , nanotechnology , metallurgy , composite material , thermal conductivity , crystallography , chemistry , chromatography , thermodynamics , physics
This paper concerns the growth of Ge thin films doped with various dopants (B, Sb, Au) by magnetron sputtering in Ar plasma under constant or pulsed powering. The aim of this work was to correlate the structural properties of Ge films with their capability to generate thermoelectric power. The films were prepared at varying sputtering deposition parameters (i.e. supplying power and substrate temperature). For the deposition at low temperatures (623 K) and with the addition of boron or antimony to target surface, the films tend to grow in microcrystalline or amorphous structure. The amorphous as‐sputtered films convert into polycrystalline ones during thermal treatment in vacuum at the temperature above 723 K. However, when Ge and Au are co‐sputtered, the polycrystalline films containing crystallites of both Ge and Au phases are formed regardless of the substrate temperature during deposition (406‐1040 K). For various films the efficiency of thermoelectric power in the range of 2 · 10 ‐10 to 6 · 10 ‐6 W · K ‐2 cm ‐1 was obtained. The results presented here suggest that both the grain size of Ge phase and dopant activation are dominant factors in determining the efficiency of thermoelectric power. From our experiments, the proper deposition conditions or annealing for maximizing the efficiency value can be obtained. For Ge‐Au and Ge‐Sb films these values were comparable to that of poly ‐ Si.