Strong emission from As monolayers in AlSb

Citation
Er. Glaser et al., Strong emission from As monolayers in AlSb, PHYS REV B, 59(3), 1999, pp. 2240-2244
Citations number
17
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B-CONDENSED MATTER
ISSN journal
01631829 → ACNP
Volume
59
Issue
3
Year of publication
1999
Pages
2240 - 2244
Database
ISI
SICI code
0163-1829(19990115)59:3<2240:SEFAMI>2.0.ZU;2-B
Abstract
Strong photoluminescence (PL) bands between 1.41 and 1.62 eV have been obse rved from superlattices (SL's) composed of fractional or single monolayers (ML) of AlAs separated by 22-49 ML of AlSb. The emission exhibits a weak de pendence on the SL period but shifts significantly to higher energy with de creasing AlAs thickness. Optically detected magnetic-resonance (ODMR) exper iments at 24 GHz on the 1.45-eV PL from the SL's with similar to 1 ML of Al As reveal S = 1/2 electron spin transitions with g(parallel to) = (1.916- 1 .923) +/- 0.002 and g(perpendicular to) = (1.934- 1.944) +/- 0.002 split by an exchange interaction (Delta) of (3.4-8.0) +/- 0.2 mu eV with holes deri ved from the J(z)= +/- 3/2 valence band. Exchange-split electron resonances with g(parallel to) = 1.868+/-0.002 and g(perpendicular to) = 1.882 +/- 0. 002 and Delta = 19.5+/-0.5 mu eV were detected on the 1.62-eV band from a s ample with 31 ML of AlSb and 0.27 ML of AlAs. The PL and ODMR results can b e understood using a type-II band lineup with the electron localized at the AlAs ML and the hole excluded to the AlSb layers. The electron g values an d the strength of the exchange interaction reflect the degree of wave-funct ion penetration into the adjacent AlSb barriers. The weakly bound excitons are localized at fluctuations along the AlSb/AlAs interfaces. [S0163-1829(9 9)00303-3].