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Title: Thermal stability of simple tetragonal and hexagonal diamond germanium

Here, exotic phases of germanium, that form under high pressure but persist under ambient conditions, are of technological interest due to their unique optical and electrical properties. The thermal evolution and stability of two of these exotic Ge phases, the simple tetragonal (st12) and hexagonal diamond (hd) phases, are investigated in detail. These metastable phases, formed by high pressure decompression in either a diamond anvil cell or by nanoindentation, are annealed at temperatures ranging from 280 to 320 °C for st12-Ge and 200 to 550 °C for hd-Ge. In both cases, the exotic phases originated from entirely pure Ge precursor materials. Raman microspectroscopy is used to monitor the phase changes ex situ following annealing. Our results show that hd-Ge synthesized via a pure form of a-Ge first undergoes a subtle change in structure and then an irreversible phase transformation to dc-Ge with an activation energy of (4.3 ± 0.2) eV at higher temperatures. St12-Ge was found to transform to dc-Ge with an activation energy of (1.44 ± 0.08) eV. Taken together with results from previous studies, this study allows for intriguing comparisons with silicon and suggests promising technological applications.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3] ;  [4] ;  [1] ; ORCiD logo [1]
  1. The Australian National Univ., Acton, ACT (Australia)
  2. Univ. of Melbourne, VIC (Australia)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. The Australian National Univ., Acton, ACT (Australia); RMIT Univ., Melbourne, VIC (Australia)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; Project No. 7620.
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 122; Journal Issue: 17; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1409261
Alternate Identifier(s):
OSTI ID: 1407838

Huston, Larissa Q., Johnson, Brett C., Haberl, Bianca, Wong, Sherman, Williams, James S., and Bradby, Jodie E.. Thermal stability of simple tetragonal and hexagonal diamond germanium. United States: N. p., Web. doi:10.1063/1.5002705.
Huston, Larissa Q., Johnson, Brett C., Haberl, Bianca, Wong, Sherman, Williams, James S., & Bradby, Jodie E.. Thermal stability of simple tetragonal and hexagonal diamond germanium. United States. doi:10.1063/1.5002705.
Huston, Larissa Q., Johnson, Brett C., Haberl, Bianca, Wong, Sherman, Williams, James S., and Bradby, Jodie E.. 2017. "Thermal stability of simple tetragonal and hexagonal diamond germanium". United States. doi:10.1063/1.5002705.
@article{osti_1409261,
title = {Thermal stability of simple tetragonal and hexagonal diamond germanium},
author = {Huston, Larissa Q. and Johnson, Brett C. and Haberl, Bianca and Wong, Sherman and Williams, James S. and Bradby, Jodie E.},
abstractNote = {Here, exotic phases of germanium, that form under high pressure but persist under ambient conditions, are of technological interest due to their unique optical and electrical properties. The thermal evolution and stability of two of these exotic Ge phases, the simple tetragonal (st12) and hexagonal diamond (hd) phases, are investigated in detail. These metastable phases, formed by high pressure decompression in either a diamond anvil cell or by nanoindentation, are annealed at temperatures ranging from 280 to 320 °C for st12-Ge and 200 to 550 °C for hd-Ge. In both cases, the exotic phases originated from entirely pure Ge precursor materials. Raman microspectroscopy is used to monitor the phase changes ex situ following annealing. Our results show that hd-Ge synthesized via a pure form of a-Ge first undergoes a subtle change in structure and then an irreversible phase transformation to dc-Ge with an activation energy of (4.3 ± 0.2) eV at higher temperatures. St12-Ge was found to transform to dc-Ge with an activation energy of (1.44 ± 0.08) eV. Taken together with results from previous studies, this study allows for intriguing comparisons with silicon and suggests promising technological applications.},
doi = {10.1063/1.5002705},
journal = {Journal of Applied Physics},
number = 17,
volume = 122,
place = {United States},
year = {2017},
month = {11}
}