Abstract:
The main achievement of this thesis is the development of a two-sheet charge simulation
model with space charge creation by trap-to-band impact ionization to describe the
electrical characteristics of alternating-current thin-film electroluminescent (ACTFEL) devices.
The two-sheet charge model localizes all of the space charge in the phosphor region
of an ACTFEL device at two sheets of positive charge. The locations of these two sheets
represent charge centroids within the phosphor region of the ACTFEL device. Simulation
results demonstrate that space charge creation by trap-to-band impact ionization yields
more capacitance-voltage (C-V) and internal charge-phosphor field (Q-F[subscript p]) overshoot
than when space charge is created by field emission from bulk traps within the phosphor
region of an ACTFEL device. The increased C-V and Q-F[subscript p] overshoot observed in simulation
when trap-to-band impact ionization is employed as the mechanism for space charge
creation corresponds to trends observed experimentally in SrS ACTFEL devices.
Several of the model parameters are varied to determine the sensitivity of the simulation
to these parameters. The parameters with the greatest influence on simulation
performance include the trap density in the phosphor region, the value of the series resistance
used in the experimental test circuit, and the characteristic fields for trap-to-band
impact ionization, band-to-band impact ionization, and electron capture.
