In this paper

time-resolved photoluminescence(TRPL) was applied to study the optical properties of partially ordered quaternary (Al

x

Ga

1-x

)

0.51

In

0.49

P(

x

=0.29) alloy grown by MOVPE

the process of the transfer of carriers and the blue-shift of PL peak in (Al

x

Ga

1-x

)

0.51

In

0.49

P(

x

=0.29) alloy are directly observed.Both excitation-wavelength dependence of lifetime and excitation-intensity dependence of lifetime show wide distribution of carriers along bands.In TRPL spectra measured at 77K

the PL peak almost keeps unchanged

while at 300K

the PL peak has a small blue-shift with the delay of time

which is completely opposite to the character of donor-acceptor pair (DAP). The blue-shift phenomenon apparently suggests the occurrence of transfer of carriers and is coincident with the report of the Z-shape character of the PL temperature-dependent spectra

in which an anomalous blue-shift of PL peak energy occurs between 55K and 84K. This phenomenon further indicates the existence of sub-bands which is derived from the superlattice effect of ordered structure

which is a so-called orientational superlattice structure and which is considered to be a composite of the low-band-gap ordered domains in a high-band-gap disordered matrix. Thus

this phenomenon verifies our conjecture about band-folding effect of conduction band from L band to Γ band

i.e.

the carriers transfer from Γ band to L band during the decay time. The transfer of carriers between Γ and L band reveals the origin of the anomalous blue-shift in the PL temperature-dependent spectra as well. The single exponential component fitting equation suggests the same category carriers of Γ band and L band. The transfer of carriers at 300K is more apparent than that at 77K. This is because that the blue-shift effect of PL peak energy occurs during 55～84K

the luminescence is dominated by L band at 300K and it is easier for the carriers to get energy to transfer under higher temperature.