Deep levels in the

n

-Al

0.05

Ga

0.95

As active layer of Al

x

Ga

1-x

As/GaAs double-heterostructure light-emitting diode have been studied by using DLTS and single shot transient capacitance methods. Two electron traps and one hole trap were detected for all six oxygen-contaminated samples. DLTS peaks were studied at 145K

171K and 125K respectively. However

no electron trap can be detected for three samples that have not been contaminated with oxygen. Therefore

we consider that the electron traps are probably related to impurity oxygen. Meanwhile

the electron trap whose DLTS peak is located at 145K was characterized in detail. Firstly

the electron emission activation energy △

E

σ of 0.29eV of this trap was determined from an Arrhenius diagr.am. The DLTS peak shifts to lower temperatures while bias pulse duration increases. This shift may be caused by the change of electron capture cross section because the change of electron emission activation energy was not observed. Secondly

the electron capture activation energy △

E

σ of 0.26eV was determined by measuring the dependence of amplitude of DLTS peaks on bias pulse duration. The electron capture cross section corresponding to infinite temperature o. was determined to be 1.9×10

-12

cm

2

. Single shot transient capacitance technique of directly measuring the capture transient spectroscopy was also used for the first time and the electron capture activation energy △

E

σ obtainded is 0.26eV to 0.28eV in accord with the result of the method mentioned before. △

E

σ varing from 0.26eV to 0.28eV is due to the change of evaculating pulse duration Such phenomenon can be interpreted as a result of composition fluctuation or mutiple origins of this electron trap. Finally

it was found that the junction capacitance of the diode shows manifest temperature depeneence. This is caused by the temperature dependence of carrier concentrations in Gedoped

p

-Al

x

Ga

1-x

As and Te-doped

n

-Al

x

Ga

1-x

As confinement layers.