HIGH MODULATION FREQUENCY LIGHT EMITTING DEVICE EXHIBITING SPATIAL RELOCATION OF MINORITY CARRIERS TO A NON-RADIATIVE RECOMBINATION REGION

摘要

A light emitting device is constructed so as to provide a first part that includes a source of excess minority carriers including excess electron-hole pairs; a second part, coupled to the first part, that includes a minority carrier barrier; and a third part, coupled to the second part, that includes a region that exhibits a low radiative recombination efficiency and a short minority carrier lifetime. In response to a first stimulus minority carriers are constrained by the second part to remain in the first part, leading to an increase of minority carrier radiative recombination in the first part and an increase in light emission; while in response to a second stimulus the minority carriers are enabled to cross the minority carrier barrier of the second part to enter the third part, leading to a decrease of minority carrier radiative recombination in the first part and a decrease in light emission. In certain embodiments the first stimulus includes an absence of an electrical signal applied between the second part and the third part, and the second stimulus comprises a presence of the electrical signal applied between the second part and the third part. In other embodiments the first stimulus includes a change in an electric field in the second part that is generated by optically induced electron-hole pairs in the second part, and the second stimulus includes an absence of the change in the electric field. In another embodiment the reverse is true. In certain embodiments the first or second stimulus can be the presence of modulating light incident on the second part and a resultant decrease in band bending. The first part can include, by example, a light emitting diode, a laser diode, a resonant cavity LED, or a vertical cavity surface emitting laser device. In another, all optical embodiment the first part includes a material that, in response to optical pumping, provides a photoluminescent emission. The second part can include a resonant tunneling structure or a potential barrier structure formed by compositional grading or impurity concentration grading. The third part can include a low temperature grown material and/or a Schottky barrier contact. It is shown that embodiments of this invention are capable of exhibiting optical gain, and an optical semiconductor light emitting device with optical gain (SLEDOG) is thus made possible.