The influence of insulator properties on the electro-optical performance of flexible ZnS:ErF3 alternating current thin film electroluminescent devices

Autor: Eric Forsythe, Dave Chiu, Nigel D. Shepherd, David C. Morton
Rok vydání: 2006
Předmět:
Zdroj: Thin Solid Films. 515:2342-2346
ISSN: 0040-6090
DOI: 10.1016/j.tsf.2006.04.032
Popis: We have developed flexible ZnS:ErF 3 alternating current thin film electroluminescent devices on molybdenum foils, and quantified the effect of insulator properties for the case of alumina (Al 2 O 3 ) and barium tantalate (BaTa 2 O 6 ) on the device electrical characteristics, and infrared emission. The inverted, full-stack structures could be flexed in tension and compression without mechanical failure or deterioration of optical output, and flex radii of a few centimeters are routinely achieved. Thus, the feasibility of a flexible, inorganic, large area electroluminescent emitter has been demonstrated. Compared to the Al 2 O 3 devices, the numbers for structures employing BaTa 2 O 6 represent a 29% increase in flux density at 980 nm, a 36% increase at 1540 nm, an 18% increase in conduction charge, a 10% increase in phosphor field and a 14% increase in threshold voltage. Our interpretation of the data is as follows: in the case of BaTa 2 O 6 , the interface states from which electrons are sourced into the phosphor are deeper, requiring a higher voltage for field emission. As a consequence, electrons are injected into the phosphor when the phosphor field is higher, resulting in better excitation efficiency and improved optical generation. The increase in conduction charge is interpreted as a higher density of interface states, which appear to have a narrower energy distribution based on the more abrupt threshold behavior observed.
Databáze: OpenAIRE
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