Molecular-beam epitaxy growth and nitrogen doping of ZnSe1−xTex alloys grown on InP substrates

Abstract

High-quality ZnSe1−xTex alloys spanning the entire compositional range have been grown by molecular-beam epitaxy. Good compositional control can be obtained by adjusting the beam equivalent pressure ratio of Se to Zn during growth. Double-crystal x-ray rocking curves with full widths at half maximum as narrow as 70 arcsec were obtained suggesting excellent crystalline quality. The p-type doping with nitrogen of ZnSe1−xTex alloys having Te contents from 0% to 100% has been systematically studied. The free hole concentration increases from 1017 to 1019 cm−3 as the Te content increases from 12% to 40%. The N-doped ZnSeTe lattice matched to InP has a free hole concentration of 2×1019 cm−3. This highly doped material was used as the p-type ohmic contact layer in light-emitting diodes made from ZnCdMgSe/ZnCdSe quantum-well structures grown on InP substrates that emit in the red, green and blue regions.