Accession Number:

AD0614200

Title:

THE EFFECT OF STRAIN ON THE EXCITON SPECTRUM OF GERMANIUM,

Descriptive Note:

Corporate Author:

BRITISH COLUMBIA UNIV VANCOUVER

Personal Author(s):

Report Date:

1964-07-27

Pagination or Media Count:

17.0

Abstract:

The intensity of optical absorption, near the absorption edge in germanium, is examined as a function of strain applied to the lattice at 90K. The results are interpreted in terms of the change of the band structure of the lattice with applied strain. The absorption edge in unstrained germanium shows a single sharp peak due to directtransition exciton formation at k 0, whereas the edge in the strained specimens shows two exciton peaks. The peak positions vary linearly with both compressional and tensional strain up to the maximum strains applied 0.1 deformation. The exciton binding energies in the strained germanium lattice, calculated within the effective mass approximation, are approximately equal and independent of the magnitude of the strain. The separation of the peaks gives for the shear deformation potentials the values b 2.7 0.3 eVunit 100 shear and d 4.7 0.5 eVunit 111 shear. The positions of the peaks give the shift of the energy gap as -10.3 1 eVunit dilation. Lattice imperfections are found to have no effect on the interpretation of the results. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE