Evidence of a second acceptor state of the E center in Si(1-x)Ge(x)

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date

2007-12

Department

Department of Applied Physics

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Language

en

Pages

4
1-4

Series

PHYSICAL REVIEW B, Volume 76, issue 23

Abstract

We have found evidence of a second acceptor state of the E center in Si1−xGex by using positron annihilation spectroscopy. To achieve this, we studied proton irradiated n-type Si1−xGex with a Ge content of 10%–30% and a P dopant concentration of 1018cm−3, in which the number of Ge atoms around irradiation induced E centers was increased by annealing. When measuring the Doppler broadening of the annihilation line, the shape parameter S starts to decreases at 150K with decreasing measurement temperature. This indicates that a charge transition in the upper half of the Si1−xGex band gap, above the well known (0/−) level, takes place. Hence, we suggest that the increased concentration of germanium around the E center pulls down the localized second acceptor state into the Si1−xGex band gap, making the Ge decorated E center a more effective trap for conduction electrons.

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Keywords

acceptor state, E center, positron annihilation spectrosopcy, Silicon germanium, vacancy

Other note

DOI

10.1103/PhysRevB.76.233202

Citation

Kuitunen , K , Tuomisto , F & Slotte , J 2007 , ' Evidence of a second acceptor state of the E center in Si(1-x)Ge(x) ' , Physical Review B , vol. 76 , no. 23 , 233202 , pp. 1-4 . https://doi.org/10.1103/PhysRevB.76.233202

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https://urn.fi/URN:NBN:fi:aalto-201805222315

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[article-cris] Perustieteiden korkeakoulu / SCI