Optical properties versus growth conditions of CdTe submonolayers insertedin ZnTe quantum wells

Standard and piezomodulated optical spectroscopy is performed on ZnTe quant um wells embedding integer and fractional monolayers of CdTe. The samples, grown in a molecular-beam-epitaxy setup on the (001) surface of ZnTe substr ates, all basically consist of 120-ML-wide ZnTe/(Zn,Mg)Te quantum wells, an d some of them contain five equally spaced full or half-monolayers of CdTe, producing monomolecular islands of CdTe "buried" in the wide host ZnTe wel l. The latter behave as efficient recombination centers for excitons. In or der to change the size and the configuration of the islands, various growth parameters have been changed between the different samples, e.g., the grow th process (molecular-beam epitaxy of binaries or ternaries, or atomic-laye r epitaxy) or the temperature. From spectroscopic measurements, the influen ce of these parameters is analyzed in detail, in terms of the size of the i slands and of their in-plane spacing, or of the vertical correlation betwee n these islands. The internal strain state of the CdTe insertions and the o verall photoluminescence efficiency are also studied versus growth conditio ns. [S0163-1829(98)01047-9].