Linear Polarized Terahertz Emission under Electrical Breakdown of a Shallow Acceptor in Uniaxially Deformed Germanium

Andrianov, A. V.; Zakhar’in, A. O.; Yassievich, I. N.; Zinov’ev, N. N.

doi:10.12693/aphyspola.113.863

Cited by 2 publications

(1 citation statement)

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“…Recently, research on shallow impurities in semiconductors has regained considerable interest, because the system is a promising candidate for a simple and coherent terahertz radiation source [3]. It has been demonstrated that the terahertz radiation can be generated from group-III acceptors in Ge in the absence [4] and presence [5][6][7] of stress. Therefore, research on the stress dependence of the oscillator strengths of optical transitions between group-III acceptor states in Ge is an important issue.…”

Section: Introductionmentioning

confidence: 99%

Electric-dipole transitions between group-III acceptor states in uniaxially compressed Ge

Wang¹,

Yen²

2010

J. Phys.: Condens. Matter

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We study the electric-dipole transitions between group-III acceptor states in Ge under stress along the [001] crystallographic direction in the effective mass approximation. We systematically investigate the cases of zero stress, infinitesimal stress, and finite stress including the low-stress and the high-stress regions. Our results show quantitative agreement with experimental data at zero stress and at infinitesimal stress. The relative intensities of infinitesimal-stress-induced components of transitions from the 1Γ(8)(+) state to the nΓ(8)(-) states do not correlate significantly with the species of acceptors except for the transition to the 1Γ(8)(-) state. The oscillator strengths of some transitions are susceptible to the stress in the low-stress region (<0.3 kbar), and could be zero at a specific stress. The behaviours of the stress dependence of oscillator strengths for different transition lines are explained in terms of the compositions of the wavefunctions and the dipole matrix elements. In the high-stress region (> or approximately equal3 kbar), the ground state is s-like, and only the transitions to the p-like states can have non-negligible oscillator strengths. The photon absorbed (emitted) and associated with each electric-dipole transition between the s-like and the p-like states is polarized either parallel or perpendicular to the stress direction. We also calculate the absorption spectra for Ge:Ga at liquid-helium temperature. The results are in good agreement with experiment.

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