Details

Autor(en) / Beteiligte

• Yang, Shilian

Titel

The symmetry and thermal activation energy of the EL2 defect center in gallium arsenide

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

1993

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• The symmetry and thermal activation energy of a dominant defect center in n-type liquid encapsulated Czochralski grown gallium arsenide (GaAs) crystal, called EL2, is investigated experimentally by the deep level transient spectroscopy (DLTS) and uniaxial stress techniques. A brief presentation of what has been done and known about this defect center is given first. A numerical fitting method improved upon the standard DLTS analysis is then presented. This method deals with a situation where the standard rate window DLTS is no longer sufficient, and gives an EL2 thermal activation energy of 0.76 $\pm$ 0.001 eV, different from the 0.82 $\pm$ 0.006 eV obtained by the standard DLTS. The symmetry of the EL2 center is then investigated through a more sophisticated data analysis method. From the experimental capacitance transients data measured under uniaxial stress, which superficially appears compatible with $T\sb{d}$ symmetry, we extract reproducible defect energy level splittings under uniaxial stress and conclude that EL2 has $C\sb{3v}$ symmetry, supporting the proposed EL2 structure as the arsenic antisite and arsenic interstitial pair, $As\sb{Ga}-As\sb{i},$ with $As\sb{i}$ weakly bound to $As\sb{Ga}.$