Optical Device Materials for a Wide Visible Spectral Region

InP substrates were investigated for visible laser diodes (LDs) and light emitting diodes (LEDs), employing molecular beam epitaxy. Applying ZnCdSe/BeZnTe and MgSe/BeZnTe SLs for active and p-cladding layers, respectively, LEDs were fabri-cated on InP substrates resulting in observing visible emissions from 554 (yellow-green) to 644 nm (red). A long lifetime op-eration more than 3500 hours was achieved for yellow LEDs. LDs with ZnCdSe active layers were fabricated, and were char-acterized at 77 K. Yellow-green lasing emissions around 560 nm were successively obtained. For BeZnSeTe, single peak pho-toluminescence emissions from 506 to 487 nm were observed for the Be composition from 0.11 to 0.2. Applying BeZnSeTe for active layers, LEDs emitting yellow light at 575 nm were fabricated. Aging tests of the BeZnSeTe LEDs showed a long lifetime operation more than 3000 hours. New concept ZnTe/CdSe SL n-contact and MgSeTe/ZnTe SL barrier structures were proposed to fabricate visible LEDs on ZnTe substrates. Bandgap energy and refractive indices of ZnCdTe, ZnCdSeTe, and MgZnSeTe were systematically evaluated. Based on these technologies and material properties, ZnCdTe/MgZnSeTe LEDs were fabricated, which produced yellow light emissions around 583 nm