S. Bhaskaran et al., ELECTRON EJECTION PROCESSES AT INSULATOR-SEMICONDUCTOR INTERFACES IN ACTFEL DISPLAY DEVICES, I.E.E.E. transactions on electron devices, 42(10), 1995, pp. 1756-1762
Luminance, conduction current and threshold voltage of ZnS:Mn ac thin
film electroluminescent display devices were measured as functions of
device temperature (10 K-300 K) and risetime of the excitation voltage
pulse (2 mu s-50 mu s). Results provided insight into the electron ej
ection mechanism at the insulator-phosphor interfaces. It was found th
at the distribution of interface state electrons at the beginning of t
he excitation voltage pulse varied substantially with device temperatu
re. Pure tunneling is thought to be the dominant electron ejection mec
hanism at the beginning of the voltage pulse while phonon-assisted tun
neling is responsible for altering the interface electron distribution
during the interval between the pulses. A delay of several microsecon
ds was observed in the build up of the transferred charge. It is attri
buted to the relatively small population of electrons available at the
insulator-phosphor interface.