Structural Analysis of Intrinsic Defects in GaAs and AlxGa1?xAs by Magnetooptically Detected Magnetic Resonance Spectroscopy

AsGa+ antisites identified by electron spin resonance as a main interface defect system in thermal GaAs/native oxide structures

“…33 As to ESR, one tenaciously defended discrimination appears to have been reached regarding two occurring variants, the isolated As Ga þ and the As Ga þ -As i complex, where As i represents an As interstitial at a second nearest interstitial site T d2 . 26,29 The latter complex has been identified with the electrically well known EL2 deep double donor center, with the þþ/þ and þ/0 charge transition levels at 0.54 and 0.75 eV above the valence band top E vb , respectively. It is responsible for the semi insulating properties of as-grown GaAs, and figures as main culprit in causing Fermi level pinning at GaAs/insulator interfaces.…”

“…As it appears, distinguishing between the types on pure ESR basis (g, a iso, DB pp ) is not straightforward. 26,31 As advanced, the most discriminating criterion advanced would be the dissimilar photosensitivity of the different variants of As Ga -centered defects, i.e., the 1.1 eV photoquenching of the EL2 center and thermal regeneration at $140 K onward; 26,29,30,32 Yet, if attempting, on the basis of the observed hf splitting, line FIG. 3.…”

“…26,[29][30][31][32] This is particularly so with respect to the studied electrical and optical properties of centers in GaAs and has been addressed in detail before. 26 It has been controversially discussed for a few decades, the outcome perhaps still not being fully settled. 33 As to ESR, one tenaciously defended discrimination appears to have been reached regarding two occurring variants, the isolated As Ga þ and the As Ga þ -As i complex, where As i represents an As interstitial at a second nearest interstitial site T d2 .…”

“…25 It is found stable to annealing up to $850 C. 32,34 The isolated As Ga þ site, a double donor like EL2, has its þþ/þ level in the range 0.4 eV-0.6 eV above E vb . 26 In regard of the current work, one may then wonder about which type of antisite-related defect is observed. As it appears, distinguishing between the types on pure ESR basis (g, a iso, DB pp ) is not straightforward.…”

Defects in Dilute Nitrides

“…(1) are the electron Zeeman and hyperfine interaction terms, respectively; µ B denotes the Bohr magneton. The obtained A value is about 20% smaller than that known for the isolated As Ga in GaAs [17,18], suggesting that the revealed defect is a complex involving As Ga . The microscopic structure of the complex does not depend on the N composition in the GaN x As 1−x layers for x = 1−3%, as the defect parameters do not change with x.…”