Increasing attention has been recently paid to the deep centers in Ⅲ-Ⅴ semiconductor alloys since the main electronic properties of these materials vary continuously with their compositions and a large range of compositions can be selected for optimizing their applications such as for luminescence

laser and microelectronic devices. On the other hand

research on the dependence of deep center characteristics on alloy compositions can offer the possibilities to gain the important information about the centers from the point of view of defect physics.In this paper we report the measurement results for the nonexponential thermal transient capacitance and DLTS spectra in Fe-doped GaAsP alloy for large range of compositions.Samples used in this study were p

+

n

diode

n

-type

GaAsP layers were grown on substrates of GaAs(for x

<

0.5) and GaP(for x

>

0.5) using MOVPE. The p

+

layers were obtained by Zn diffusion

iron impurities were also diffused into samples and their concentrations were selected in the range of

N

Fe

/

N

D

~0.05. The composition

x

of each samples studied was measured by microprobe analysis in a scanning electron microscope with uncertainty less than ±2%.