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Atomic layer deposition process for novel quantum dot light emitting diodes
Technology:
Atomic layer deposition process for novel quantum dot light emitting diodes (QD-LEDs)
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Quantum-dot light-emitting diodes (QD-LEDs) are the next generation of LED technology with applications in televisions, computer screens, lighting and beyond. Quantum dots (QD) are tiny crystals that emit rich colorful light when stimulated by an electric current. These next-generation LEDs provide excellent spectral purity, wide-range tunability and the potential for improved efficiency.
Innovations and Advantages
A team of Harvard engineers led by Prof. Narayanamurti has devised a new device architecture based on a monolayer of quantum dots sandwiched between two inorganic conducting layers. Taking advantage of the surface chemistry of the quantum dots, atomic layer deposition (ALD) is used to deposit an ultra-thin layer of aluminum oxide to isolate individual quantum dots (see figure), thus effectively reducing inter-dot coupling. When the tunneling current passes through the quantum dots, each dot lights up like a light bulb, and their sum gives the total light intensity of the device. The advantages of this new device architecture are threefold. First, the usage of a single quantum dot layer pushes the material cost to be minimal. Second, due to reduced inter-dot coupling, this architecture has the potential to further improve device efficiency. Third, the new architecture allows high-current density, which could be promising for the realization of high-brightness devices or lasers. Looking beyond the obvious applications in lighting and displays, this new technology has potential applications in field-effect transistors, flash memory chips and solar cells.
The Al2O3 layer deposited by ALD isolates individual quantum dots, allowing
high-density current to pass through the dots only. (Courtesy: E. M. Likovich)
Additional Information
See press release here: http://www.seas.harvard.edu/news-events/press-releases/quantum-dot-leds
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Inventor(s):
Jaramillo, Rafael
Likovich, Edward
Narayanamurti, Venkatesh
Russell, Kasey J.
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For further information, please contact:
Mick Sawka, Director of Business Development
(617) 496-3830
Reference Harvard Case #4144