The nitrogen doped

p

-type ZnSe on (100) GaAs substrates has been grown by atmospheric pressure (AP) metal organic chemical vapour deposition (MOCVD).Pure NH

3

gas was used as a doping material.The nitrogen doping level was controlled by the NH

3

gas flow rate.Because sticking coefficients of NH

3

molecules appear to be very low

the NH

3

flow rate must be great enough to provide sufficient doping of N.This leads to cause degradation of the epilayer quality.Above result is clearly indicated by measurements of X-ray diffraction and photoluminescence(PL).Obtaining of

p

-type conduction in ZnSe is evidenced by measuring optical and electrical properties of N-doped ZnSe layers.At the low doping level

the PL spectrum exhibited a dominant free-to-acceptor transition (FA) emission at 460um and also exhibited deep centre emission at 580um.ZnSe layers with a low doping level have a very high resistivity.It was difficult to determine theconduction type due to a large Hall-voltage drift.Both band intensities increased with increasing NH

3

flow rate.The results indicate that the shallow acceptor and deep centre levels were formed by doping nitrogen.In the high doping level

the 77K PL of the epilayers is dominated by the deep centre emission at 580urn and the bands broadened.The ZnSe layer clearly indicated a

p

-type conduction by Hall measurements at room temperature.Hall mobilities is nearly 46cm

2

/V·s and carrier concentrations reach the order of 1016cm

3

.The p-ZnSe/n-GaAs heterojunctions exhibit good rectification properties.The forward-bias turn-on voltage is 1.5V.The results confirmed the

p

-typeconduction of the N-doped ZnSe layers with a high doping level.