FEDdevices operate at much lower accelerating voltages

so the driving currents have to be greatly increased to maintain adequate brightness.Surface degradation of the phosphor occurs due to reaction with residual gases in the vacuum

and this is exacerbated by the higher current density.This degradation leads to decrease brightness of screen.In addition

the volatile by-products from the phosphor surface cause poisoning of the field emitter tips.Consequently

the FEDdevice ages at an accelerated rate.The low-voltage properties of ZnS:Zn

Pb were investigated for applications.Because of decomposition by irradiation of electron beam and generates of harmful gases such as SO

2

for field emitter array

the surface coating and encapsulation of phosphors is an important technique to improve low-voltages cathodoluminescence and chemical stability and to reduce outgassing.SiO

2

was used as the coating material because of its favorable band alignment when forming a heterojunction with ZnS.SiO

2

exhibits minimal losses in electron penetration and has a penetration depth nearly twice as large as that of ZnS.At low excitation voltage

the surface of ZnS:Zn

Pb gets charged because of their higher resistivity.It is necessary to reduce the resistivity of the phosphor in order to improve its low voltage cathodoluminescent properties.To lower the resistivity of the ZnS:Zn

Pb

mixing the phosphor with In

2

O

3

conductive powder have been reported.The low voltage cathodoluminescent properties of this phosphors mixed with and without In

2

O

3

conductive powder are studied in this investigation.When mixed with In

2

O

3

the critical voltage will decrease from 80 Vto 8 V.The CLemission intensity against voltage of ZnS:Zn

Pb is more efficient than ZnS:Ag

Cl and ZnS:Zn.The blue phosphor ZnS:Zn

Pb has an excellent luminescence properties and saturation properties under high current density.It is shown that ZnS:Zn

Pb can be used as FEDphosphor.