Effect of Pressure on Hopping Conduction in Amorphous Ge Alloys
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The electrical conductivity σ has been measured at pressures P to 8 GPa and temperatures T of 77-300K in evaporated amorphous Ge (a-Ge), a-Ge-Cu alloys and a-Ge-Al alloys. The T dependence of σ is well described by a power law at low temperatures below 150 K, which is expected from a multi-phonon tunneling transition process model with weak electron-lattice coupling, rather than the Mott's variable range hopping conduction model. The exponent n in the power law changes with increasing pressure. For both a-Ge<SUB>1-x</SUB>Cu<SUB>x</SUB> and a-Ge<SUB>1-x</SUB>Al<SUB>x</SUB> alloys, d (ln n) /dP show positive values in the low pressure region and negative values in the high pressure region. Results are discussed from several hopping conduction models.
- The Review of High Pressure Science and Technology
The Review of High Pressure Science and Technology 7, 647-649, 1998
The Japan Society of High Pressure Science and Technology