As a versatile wide band gap semiconductor material

ZnO has a variety of applications including gas sensors

piezoelectric devices

field effect transistors

solar cells

and so on. Particularly

the application of ZnO in blue and ultraviolet light emitting diodes (LED) and laser diodes(LD) have attracted much attention in the past ten years

because it has the wide-bandgap of 3.37 eV at room temperature (RT) and the large exciton binding energy of 60 meV. Many growth techniques for single-crystalline ZnO films have been used

such as molecular beam epitaxy (MBE)

metal-organic chemical vapour deposition(MOCVD)

RF magnetron sputtering

and pulsed laser deposition (PLD). Among these techniques

MOCVD has many advantages for the semiconductors production and has been used to manufacture many semiconductor devices. MOCVD growth of ZnO requires appropriate zinc and oxygen precursor. For the group Ⅱ element

the mostly used zinc precursor is a metal-organic compounds like diethyl (DEZn) and dimethyl (DMZn). For the group Ⅵ precursor

a large number of oxygen-containing compounds was widely used: gases like O

2

CO

2

NO

N

2

O;water and several types of organic compounds like alcohols

aldehydes

ketons. During the growth of ZnO

kinds of carrier gas were used to introduce zinc and oxygen precursor into growth chamber. Because of the huge volume of the carrier gas and the likely reaction with zinc precursor or oxygen precursor

it has the obvious influence on the quality of ZnO. In this experiment

argon(Ar)

nitrogen (N

2

)and hydrogen (H

2

) were used to compare their effect on the growth of ZnO;DMZn were used as the zinc precursor and N

2

O as oxygen precursor.ZnO films were grown on quartz substrate by LP-MOCVD. Crystalline quality

and Optical properties were studied with photoluminescence

X-ray diffraction (XRD) using Cu Kα (λ=0.154056 nm)

Raman spectra. The growth rate of ZnO was measured with the step profiler. Compared to Ar

the optical properties were improved by using H

2

as the carrier gas of N

2

O. The quantity of unintended doped carbon was decreased. Ionization strengthened the ultraviolet emission and weakened the visible emission of ZnO films. According to the measure of XRD

the ZnO films had (0002) preferred orientation.