TY - JOUR
T1 - Space-charge effects in type-II strained layer superlattices
AU - Bradley, I.V.
AU - Creasey, J.P.
AU - O'Donnell, K. P.
PY - 1998/2/2
Y1 - 1998/2/2
N2 - The low-temperature photoluminescence (PL) spectra of a range of CdS-CdSe and CdS-ZnSe type-II superlattices was measured under both cw and quasi-cw excitation over the excitation range from mW cm-2 to MW cm-2. In all cases, a single PL band due to the recombination of separated electrons and holes in the type-II bandstructure was observed. As the excitation density increases from a low value, the PL peak shifts logarithmically towards the blue. Total shifts of up to 200 meV for a CdS-CdSe sample of 10 nm period are observed, with a corresponding shift-factor of 30 meV per decade of excitation density. The shift factor increases in a regular fashion with the superlattice period. A comparison with the literature shows that a logarithmic dependance of the blue shift with increasing excitation density appears to be a universal feature of type-II SL, even in the absence of strain.
AB - The low-temperature photoluminescence (PL) spectra of a range of CdS-CdSe and CdS-ZnSe type-II superlattices was measured under both cw and quasi-cw excitation over the excitation range from mW cm-2 to MW cm-2. In all cases, a single PL band due to the recombination of separated electrons and holes in the type-II bandstructure was observed. As the excitation density increases from a low value, the PL peak shifts logarithmically towards the blue. Total shifts of up to 200 meV for a CdS-CdSe sample of 10 nm period are observed, with a corresponding shift-factor of 30 meV per decade of excitation density. The shift factor increases in a regular fashion with the superlattice period. A comparison with the literature shows that a logarithmic dependance of the blue shift with increasing excitation density appears to be a universal feature of type-II SL, even in the absence of strain.
KW - superlattices
KW - photoluminescence
KW - strained layer superlattice
UR - http://www.scopus.com/inward/record.url?scp=0000680036&partnerID=8YFLogxK
U2 - 10.1016/S0022-0248(98)80152-8
DO - 10.1016/S0022-0248(98)80152-8
M3 - Article
AN - SCOPUS:0000680036
SN - 0022-0248
VL - 184-185
SP - 728
EP - 731
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
ER -