Graduation date: 1995

Thesis (Ph. D.)--Oregon State University, 1982. / Typescript (photocopy). Includes bibliographical references (leaves 174-179). Also available on the World Wide Web.

Alternating-current thin-film electroluminescent (ACTFEL) devices are used in the formation of pixels in flat panel displays. ACTFEL flat panel displays have many advantages over other flat panel technologies. Specifically, ACTFEL panels are emissive displays, they have high brightness, wide viewing angles, and rugged construction. Although much is already known about the operation of ACTFEL devices, several topics related to the device physics and modeling of these devices require further research. In this work, existing ACTFEL device models are refined by expanding the understanding of ACTFEL device physics and operation. Modeling is separated into three levels of increasing complexity as follows; (1) equivalent circuit modeling, (2) device physics or electrostatic modeling, or (3) Monte Carlo modeling. Each level of model is addressed in this thesis. Existing equivalent circuit models are empirically refined to account for device response to variations in the shape of the driving waveform pulse. The device physics model is expanded by presenting evidence for the formation of space charge in the phosphor layer and the equations prescribing device response are modified accordingly. Also, a new technique for measuring the distribution of interface states in ACTFEL devices is presented. This gives new insight into device operation, as the interface state distribution is one of the most difficult parameters to estimate/measure in the device physics model. Finally, an experiment is presented which attempts to measure the maximum energy of hot electrons during conduction in the phosphor. This research leads to a recommendation of the complexity of the conduction band model needed for accurate Monte Carlo simulation of ACTFEL devices. / Graduation date: 1993

Graduation date: 1994

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 178-187). Also available in print.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references. Also available in electronic version.

No description available.

No description available.

The objective of the research presented in this thesis is to develop, implement, and demonstrate the utility of an n-sheet, state-space alternating-current thin-film electroluminescent (ACTFEL) device model. In this model, the phosphor layer is discretized into n + 1 layers, with band-to-band impact ionization, space charge creation/ annihilation, and luminescent impurity excitation/do-excitation occurring only at n sheets between the n + 1 layers. The state-space technique is a structured approach in which the ACTFEL device physics implementation is separated from the ACTFEL measurement circuit electrical response, resulting in a set of coupled, first-order differential equations which are numerically evaluated. The device physics implementation begins with electron injection from phosphor/insulator interfaces and band-to-band impact ionization. Phosphor layer space charge generation via band-to-band impact ionization and subsequent hole trapping, trap-to-band impact ionization, and shallow donor trap emission are then added to the model. Finally, impact excitation and radiative relaxation are added to the model to account for ACTFEL device optical properties. The utility of the n-sheet, state-space ACTFEL device model is demonstrated in simulations which verify hypotheses regarding ACTFEL device measured characteristics. The role of phosphor layer hole trapping and subsequent thermionic emission in SrS:Cu ACTFEL device EL thermal quenching is verified via simulation. Leaky ACTFEL device insulators are shown to produce high luminance but low efficiency. A novel space charge estimation technique using a single transferred charge curve is presented and verified via simulation. Hole trapping and trap-to-band impact ionization are shown to produce realistic overshoot in C-V curves, and each results in a different phosphor layer space charge distribution. DC coupling of the sense capacitor used in the measurement circuit to the applied voltage source is required for the generation of ACTFEL device electrical offset, as verified by simulation. Shallow donors are identified as a probable SrS:Ce ACTFEL device leakage charge mechanism. A field-independent emission rate time constant model is shown to yield realistic ZnS:Mn ACTFEL device leakage charge trends. / Graduation date: 2001

The goal of this thesis study is to develop an activated reactive evaporation (ARE) system and to demonstrate its utility by fabricating-alternating current thin-film electroluminescent (ACTFEL) oxide phosphor devices. ARE entails evaporation in an activated gas. The main ARE system components are three thermal evaporation sources, a microwave power supply, an electron cyclotron resonance plasma (ECR) source, a substrate heater/controller, a film thickness monitor, and a leak valve for gas flow control. Ga���0���:Eu ACTFEL devices are fabricated using the ARE system. The maximum Ga���O: deposition rate is approximately 2 nm/s. As-deposited films are transparent, insulating, and amorphous with an index of refraction of 1.68 and an optical bandgap of 4.25-4.9 eV. Ga���O��� films are typically amorphous until annealed above 1000��C in a furnace or by rapid thermal annealing. However, when hydrothermal annealing is employed, Ga���O��� films crystalize at temperatures as low as 450��C. Electrical and optical characterization indicates that the Ga���O���:Eu ACTFEL devices have very little charge transfer and emit very dim, orange-red electroluminescence with an emission peak of about 615 nm. / Graduation date: 2001