Two novel acceptors in ultra-pure germanium: nature and interconversion
Experimental data on two shallow acceptors A/sub 4/ and A/sub 3/ /sub 5/ in pure germanium are presented. The two acceptors appear with concentrations up to approx. 10/sup 11/ cm/sup -3/ always and only in ultra-pure germanium single crystals which have been grown in a pure N/sub 2/ ambient from a melt contained in a graphite crucible. The bound excited state spectra of both acceptors are hydrogenic. The ground state of A/sub 4/ is a GAMMA/sub 8/ quadruplet while the A/sub 3/ /sub 5/ acceptor exhibits a ground state manifold consisting of at least two Kramers doublets, one with GAMMA/sub 6/ and the other with GAMMA/sub 7/ symmetry. The energy splitting between the two doublets is 1.1 MeV and it is symmetric in relation to the position of the A/sub 4/ ground state. Complete and reversible interconversion can be induced with appropriate thermal annealing. The experimental results suggest that A/sub 4/ and A/sub 3/ /sub 5/ are two forms of one center. Above 700/sup 0/K the A/sub 4/ concentration decreases irreversibly following an exponential decay. Interconversion can be observed at any point during the irreversible annealing of the center. 4 figures.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6714387
- Report Number(s):
- LBL-14227; CONF-820875-1; ON: DE83000514
- Resource Relation:
- Conference: 12. international conference on defects in semiconductors, Amsterdam, Netherlands, 31 Aug 1982; Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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