Atomic layer deposition (ALD) is a technique capable of producing ultrathin conformal films with atomic level control over thickness. A major drawback of ALD is its low deposition rate, making ALD less attractive for applications that require high throughput processing. An approach to overcome this drawback is spatial ALD, i.e., an ALD mode where the half-reactions are separated spatially instead of through the use of purge steps. This allows for high deposition rate and high throughput ALD without compromising the typical ALD assets. This paper gives a perspective of past and current developments in spatial ALD. The technology is discussed and the main players are identified. Furthermore, this overview highlights current as well as new applications for spatial ALD, with a focus on photovoltaics and flexible electronics.

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A polysilicon transistor based active matrix organic light emitting diode (AMOLED) pixel with high pixel to pixel luminance uniformity is reported. The new pixel powers the OLEDS with small constant currents to ensure consistent brightness and extended life. Excellent pixel to pixel current drive uniformity is obtained despite the threshold voltage variation inherent in polysilicon transistors. considerations in the design for high information content displays are discussed.

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The design of an active matrix organic light emitting diode (AMOLED) display using a polysilicon thin film transistor pixel is described. Characteristics of the OLED response in the low current regime are described and their impact on the design of integrated driver circuitry is discussed. Integrated data and select scanners which generate the signals necessary for data capture and pixel calibration are presented.

Abstract— Significant improvement in the luminescent performance of SrxCa1−xGa2S4: Ce (0 < × < 1) EL devices was achieved by optimizing the Sr/Ca ratio and oxygen doping. The key factor for improvement is oxygen doping of thiogallate thin films. Microstructural analysis from x‐ray diffraction and transmission electron microscopy showed that oxygen doping increased crystal grain size and induced a preferred orientation along (602) planes. Photoluminescence studies showed the luminescence decay time increased with oxygen doping, indicating the suppression of non‐radiative energy transitions at structural defects, e.g., sulfur vacancies, due to improved crystalline quality of the thiogallate thin films. The emission color blue shift in oxygen‐doped Sr‐Ca mixed thiogallate was attributed to the preferential substitution of Ce3+ for Sr2+ rather than Ca2+ due to a better match of ion size and a possible ordering effect from lattice strain introduced by oxygen incorporation. The threshold‐field reduction and steeper turn‐on near threshold in oxygen‐doped devices was considered to be a result of the introduction of shallow trapping states at the insulator/phosphor interface and the elimination of bulk trapping states by oxygen doping.

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A new class of blue thin-film electroluminescent (TFEL) devices based on thiogallate phosphors has been reported recently. The purpose of the work reported herein is to compare and contrast the electrical properties of CaGaS4:Ce TFEL blue phosphor devices to those of conventional evaporated ZnS:Mn TFEL devices. Capacitance-voltage (C-V) and internal charge-phosphor field (Q-F) techniques are employed for electrical characterization.