Briefly, the present disclosure provides a device comprising: a) an LED capable of emitting light at a first wavelength; b) a re-emitting semiconductor construction which comprises a potential well not located within a pn junction; and c) a reflector positioned to reflect light emitted from the LED onto the re-emitting semiconductor construction. Alternately, the device comprises: a) an LED capable of emitting light at a first wavelength; b) a re-emitting semiconductor construction capable of emitting light at a second wavelength which comprises at least one potential well not located within a pn junction; and c) a reflector which transmits light at said first wavelength and reflects at least a portion of light at said second wavelength. Alternately, the device comprises a semiconductor unit comprising a first potential well located within a pn junction which comprises a LED capable of emitting light at a first wavelength, and a second potential well not located within a pn junction which comprises a re-emitting semiconductor construction.