ZnTe-Based light-emitting-diodes grown on ZnTe substrates by molecular beam epitaxy

We have investigated the ZnTe-based material system for the application to light-emitting devices. To this end, ZnTe homoepitaxy techniques have been developed to grow high-quality epitaxial layers. The conductivity control of ZnTe and ZnMgSeTe layers have been investigated. High structural quality n-type ZnTe layers with high carrier concentration are achieved by aluminum doping. Ambipolar conductivity control of quaternary layers is achieved. Aluminum doped ZnMgSeTe layers show a net carrier concentration of 5 × 10¹⁶ cm^-3, while a high hole concentration of 2.5 × 10¹⁹ cm^-3 is achieved by p-type doping using a nitrogen plasma source. Based on those results, Zn_1-xCd_xTe/ZnMgSeTe triple-quantum-well(TQW) LED structures were fabricated. Bright electroluminescence was obtained at room temperature at the wavelength of 604 nm from Zn_0.7Cd_0.3Te and at 566 nm from Zn_0.85Cd_0.15Te TQW-LED.