Patent ID: 8053755

Claim:
A strained semiconductor heterostructure ( 10 ) comprising: an injection region comprising a first emitter layer ( 11 ) having p-type conductivity and a second emitter layer ( 12 ) having n-type conductivity; a light generation layer ( 13 ) positioned between the first emitter layer ( 11 ) and the second emitter layer ( 12 ), the bandgap energy of said light generation layer being smaller than the ones of the first and the second emitter layers; an electron capture region ( 14 ) positioned between the light generation layer ( 13 ) and the second emitter layer ( 12 ), said electron capture region comprising a capture layer ( 16 ) adjacent to the second emitter layer, and a confining layer ( 15 ) adjacent to said electron capture layer, the bandgap energy of said confining layer being larger than that of the light generation layer, the bandgap energy of said capture layer being smaller than that of the confining layer, and the lowest energy level for electrons in the capture layer being higher than that in the light generation layer; characterized in that the widths and materials of the confining and capture layers ( 15 , 16 ) are selected to provide energy difference between one of localized energy levels for electrons in the capture layer ( 16 ) and the conduction band bottom of the second emitter layer ( 12 ) equal to the energy of the optical phonon.