Excitonic optical transitions as a probe of self-organized growth of ZnTe (CdTe) islands in (001)-grown CdTe (ZnTe) quantum wells
✍ Scribed by V. Calvo; P. Lefebvre; J. Allègre; A. Bellabchara; H. Mathieu; Q.X. Zhao; N. Magnea
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 73 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0749-6036
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✦ Synopsis
Integer or half monolayers of CdTe have been deposited, every 20 monolayers, in 120monolayer wide ZnTe/(Zn,Mg)Te quantum wells, by molecular beam epitaxy or atomic layer epitaxy on nominal (001) surfaces of ZnTe substrates. Low-temperature direct and piezomodulated reflectivity as well as C.W. and time-resolved photoluminescence have been taken from these samples. By comparison of samples grown in slightly different ways, we conclude that fractional CdTe layers, separated by a few ZnTe monolayers, grown in a Zn-rich environment, tend to grow in an ordered way: successive CdTe islands are stacked in vertical columns separated by columnar 'voids' of pure ZnTe. This behavior is the opposite of the staggered lineup of ZnTe islands in CdTe-(Cd,Zn)Te quantum wells, grown on Cd-rich substrates, recently observed by similar experimental techniques. Both behaviors are tentatively explained in terms of the relative stiffnesses of the materials of the inserts and of the matrix.