부산대학교 도서관

Cascading of active regions in InAs–GaSb superlattice light-emitting diodes (LEDs) grown by molecular beam epitaxy is demonstrated as an effective means of increasing optical emission. Devices were fabricated into $120\times 120\ \mu{\hbox {m}}^{2}$ mesas to demonstrate suitability for high resolution projection systems. Devices with 1, 4, 8, and 16 stages were designed for midwave infrared emission at 3.8 $\mu{\hbox {m}}$ operating at 77 K, and quasi-continuous-wave output powers in excess of 900 $\mu{\rm W}$ from a 16-stage LED have been demonstrated. External quantum efficiency is shown to improve substantially with cascading, approaching 10% for a 16-stage device.