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Vertical light emitting diodes

  • US 8,592,842 B2
  • Filed: 03/03/2008
  • Issued: 11/26/2013
  • Est. Priority Date: 03/02/2007
  • Status: Active Grant
First Claim
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1. A light emitting device comprising:

  • a first semiconductor layer having doping of a first type;

    a second semiconductor layer having doping of a second type;

    a light emitting region interdisposed between the first and second semiconductor layers;

    a first electrode layer disposed proximal to the first semiconductor layer and distal to the second semiconductor layer;

    a second electrode layer disposed proximal to the second semiconductor layer and distal to the first semiconductor layer; and

    a first multilayer reflector stack interdisposed between the first electrode layer and the first semiconductor layer, the first semiconductor layer having a surface facing the first multilayer reflector stack, the first multilayer reflector stack extending at least partially across the surface of the first semiconductor layer and comprising at least a first layer disposed proximal the first electrode layer and a last layer disposed distal the first electrode layer; and

    a second multilayer reflector stack interdisposed between the second electrode layer and the second semiconductor layer, the second semiconductor layer having a surface facing the second multilayer reflector stack, the second multilayer reflector stack extending only partially across the surface of the second semiconductor layer and comprising at least a first layer disposed distal the second electrode layer and a last layer disposed proximal the second electrode layer;

    wherein at least the first and the last layer of the first multilayer reflector stack are electrically conducting and optically transparent and at least the first layer and the last layer of the second multilayer reflector stack are electrically conducting and optically transparent;

    wherein at least 60% of light incident on the first multilayer reflector stack that is generated in the light emitting region is reflected by the first stack and at least 60% of the light incident on the second multilayer reflector stack that is generated in the light emitting region is reflected by the second stack;

    wherein the transverse extent of the second multilayer reflector stack is less than that of the first multilayer reflector stack;

    wherein the second multilayer reflector stack extends across at least the same part of the surface of the second semiconductor layer across which the second electrode layer also extends; and

    wherein light generated in the light emitting region is extracted from the device through those parts of the surface of the second semiconductor layer opposite to the first multilayer reflector stack but across which the second multilayer reflector stack does not extend.

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