Defect structure of degraded GaAlAs-GaAs double heterojunction lasers

Abstract
Detailed transmission electron microscopy contrast analysis is presented revealing the interstitial nature of the defect networks associated with the active region of a degraded double heterojunction GaAs laser. Three different dislocation networks with Burgers vectors of (a) a/2[011] inclined at 45° to the (001) junction plane, (b) a/2[110] lying in the junction plane and (c) a[001] normal to the junction plane have been observed and investigated. A model is proposed showing how restricted climb of dislocations threading the active region could explain the growth of dislocation networks of the types (a) and (b) and would account for the observed preferred ⟨100⟩ and ⟨110⟩ orientations of darkline defects.