HIGH EFFICIENCY ULTRAVIOLET LIGHT EMITTING DIODE WITH BAND STRUCTURE POTENTIAL FLUCTUATIONS
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Abstract
A method of growing an AlGaN semiconductor material utilizes an excess of Ga above the stoichiometric amount typically used. The excess Ga results in the formation of band structure potential fluctuations that improve the efficiency of radiative recombination and increase light generation of optoelectronic devices, in particular ultraviolet light emitting diodes, made using the method. Several improvements in UV LED design and performance are also provided for use together with the excess Ga growth method. Devices made with the method can be used for water purification, surface sterilization, communications, and data storage and retrieval.
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Citations
175 Claims
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1-156. -156. (canceled)
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157. A method for manufacturing an optical device, the method comprising:
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providing a substrate comprising a surface region into a process chamber; forming a buffer material overlying the surface region; forming an n-type material overlying the buffer material; subjecting the n-type material to a flux of an elemental gallium material to cause formation of a thickness of gallium material; transferring elemental aluminum material from an aluminum source; transferring a nitrogen species from a nitrogen source; causing formation of a crystalline aluminum, gallium, and nitrogen containing material (AlGaN) overlying the n-type material to form an active region; maintaining the process chamber under a vacuum environment; and forming a p-type material overlying the active region; and whereupon the optical device is characterized by an electromagnetic emission ranging from about 200 nm to 365 nm. - View Dependent Claims (158, 159, 160, 161, 162, 163)
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164. A method for manufacturing an optical device, the method comprising:
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providing a substrate comprising a surface region into a process chamber; transferring a flux of an elemental gallium material to cause formation of a thickness of gallium material overlying the surface region; transferring an elemental aluminum material from an aluminum source; transferring a nitrogen species from a nitrogen source; causing formation of a crystalline aluminum, gallium, and nitrogen containing material (AlGaN) overlying the n-type material such that the crystalline aluminum, gallium, and nitrogen containing material has a reduced aluminum concentration in a localized region in reference to a macroscopic aluminum concentration for the AlGaN material; and maintaining the process chamber under a vacuum environment; whereupon the localized region has the reduced aluminum concentration characterized by a reduced AlN mole fraction and has a lateral dimension in a nanometer range, up to 100 nm, 200 nm, 500 nm, or up to about 1 micron.
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165. An optical device characterized by an electromagnetic emission ranging from about 200 nm to 365 nm, the device comprising:
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a substrate comprising a surface region; a buffer material overlying the surface region; an n-type material overlying the buffer material, the n-type material comprising AlGaN characterized by a first stoichiometry, the first stoichiometry having a first aluminum percentage, the n-type material characterized by a first bandgap energy; an active region comprising a quantum well region, the quantum well region comprising a crystalline aluminum, gallium, and nitrogen containing material (AlGaN) at a second stoichiometry characterized by a second bandgap energy overlying the n-type material; an oxygen impurity concentration of less than 1×
1018 atoms per cm3 characterizing the quantum well region; anda p-type material overlying the active region. - View Dependent Claims (166, 167, 168, 169, 170, 171, 172, 173, 174, 175)
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Specification