Light emitting semiconductor device having polymer-filled sub-micron pores in porous structure to tune light scattering

A light emitting device comprising:

• a light emitting semiconductor device that in operation emits primary light;
• a wavelength converting structure disposed on the light emitting semiconductor device and configured to absorb at least some of the primary light and in response emit secondary light of longer wavelength than the primary light;
• a porous structure disposed on the wavelength converting structure opposite from the light emitting semiconductor device, formed from a material substantially transparent to the primary and secondary light and having a first index of refraction, and comprising sub-micron pores;
• and
• a polymer filling the sub-micron pores in the porous structure and having a second index of refraction different from the first index of refraction at 25° C., the polymer forming optically scattering interfaces with the porous structure that scatter primary and secondary light, a magnitude of a difference between the first index of refraction and the second index of refraction decreasing with increasing temperature of the porous structure during operation of the light emitting device, and a scattering of the primary and secondary light by the scattering interfaces consequently decreasing with increasing temperature of the porous structure during operation of the light emitting device.