Defect structure of degraded heterojunction GaAlAs−GaAs lasers

Abstract

Transmission electron microscopy has been used to study the defects associated with the degradation of broad−contact geometry double−heterostructure lasers. Two different types of dislocation networks have been observed close to the active region of the degraded device having Burgers vectors of (a/2) 〈011〉 and a〈001〉. Both networks have been shown to be of interstitial character.

Analysis of dark-line defect growth suppression in InxGa1−xAs/GaAs strained heterostructures

“…It is probably due to the transfer of interstitials from the type B defect networks to the type A ͗100͘ DLDs during annealing. 4 In other words, the observation of enlargement of ͗100͘ DLDs was related to the type A ͗100͘ DLDs. The type B defect networks could work as a sink for vacancies, thereby enhance the propagation of type A ͗100͘ DLDs.…”

“…[4][5][6][7]9,12,13 TEM contrast techniques and stereo electron micrographs have also been used in the analysis of DLDs. These results showed that DLDs in different structures have similar nature which stretch along ͗100͘ and ͗110͘ directions ͑so-called ͗100͘ DLDs and ͗110͘ DLDs͒.…”

“…Two types of the ͗100͘ DLDs have been observed in GaAs/GaAlAs structure by Hutchinson and Dobson. 4 One is due to cross-climb of threading dislocations onto ͕011͖ planes ͑type A͒. It consists of ͕011͖ loops.…”

Combined transmission electron microscopy and cathodoluminescence studies of degradation in electron-beam-pumped Zn1−xCdxSe/ZnSe blue-green lasers

“…6,30,31 Point defects, especially vacancies, have negligible diffusivities at room temperature. 32 However, the reaction probability increases if nonradiative recombination occurs in the vicinity of the defect, e.g., by a factor ϳ10 22 in Zn 0.67 Cd 0.33 Se.…”

“…29 It is therefore surprising to find vacancy loops in such proportion in our case, although such loops have also been observed in conjunction with interstitial loops in degraded III-V devices. 30 The presence of degradation-induced defects involves the formation and/or diffusion of point or extended defects during bombardment. In the following we compare the models presented in previous studies with the help of the experimental situation depicted in Fig.…”