Accoding to the calculation of hot electron impact cross section by Shen

the blue emission could be get if the hot electron have enough energy.In order to get hot electrons of relative high energy

first we choice SiO

2

/Ta

2

O

5

and SiO

2

/Y

2

O

3

complex layers as preheat layer to substitute for SiO and to prepare the devices whose preheating layers were SiO

2

/Ta

2

O

5

SiO

2

/Y

2

O

3

and SiO for samples A

B

C respectively.The electroluminescence intensity and transferred current were mesaured by using HITACH 4010 model flurescence spectrophotometer and Chen and Krupta circuit respectively.The maxmum emission intensity of C is larger one order than that of B and two order than that of A.In the mean time

the ratio among the transferred current of A and that of B and that of C is 3.9:1.8:1.0 Accoding to the following luminescence equation and experiment date

we got tile maxmum hot electron energy ill A.B

C is 0.4

0.5 and 1.5eV respectively.Then we choice ZnS and SiO

2

as accerating layer

prepared the device 2603 and 2502 respectively. The derivation electronluminscence intensity and transferred charge excited by different polaration voltage have been measured

The ratio between the electroluminescent intensity caused by electron accerated by SiO

2

and that by ZnS is 20.0:1.0.In the mean time

the transferred charge from ZnS side is larger than that from SiO

2

.Accoding to the luminescent intensity

we got the following result: the ZnS layer is prefer to provide more but low energy electrons

and SiO

2

is prefer to provide smaller quantity but high energy hot electron.Till now

it is obviously that the SiO and SiO

2

are accepterable preheating and accerating layer respectively in new designed devices.