Provided is a light emitting device including a Fresnel lens and/or a holographic
diffuser formed on a surface of a semiconductor light emitter for improved light
extraction, and a method for forming such light emitting device. Also provided
is a light emitting device including an optical element stamped on a surface for
improved light extraction and the stamping method used to form such device. An
optical element formed on the surface of a semiconductor light emitter reduces
reflective loss and loss due to total internal reflection, thereby improving light
extraction efficiency. A Fresnel lens or a holographic diffuser may be formed on
a surface by wet chemical etching or dry etching techniques, such as plasma etching,
reactive ion etching, and chemically-assisted ion beam etching, optionally in conjunction
with a lithographic technique. In addition, a Fresnel lens or a holographic diffuser
may be milled, scribed, or ablated into the surface. Stamping, an alternative method
for forming an optical element, can also be used to form a Fresnel lens or a holographic
diffuser on the surface of a semiconductor light emitter. Stamping includes pressing
a stamping block against the surface of a light emitting diode. The stamping block
has a shape and pattern that are the inverse of the desired optical element. Optionally,
stamping can be done before, after, or concurrently with wafer-bonding. Alternatively,
a material can be stamped and later bonded to the semiconductor light emitter.