Theoretical study of ultraviolet ZnO/Zn0.8Mg0.2O laser diodes on GaN or Al2O3 substrates: Toward electrically pumped devices



We propose a new type of laser structure based both on oxide and nitride semiconductors. Due to a lack of p-type conductivity in the zinc oxide, we put forward the idea to use p-type gallium nitride with ZnO/ZnMgO active region. Unfortunately, refractive index of nitrides is larger than in oxides, which means that the transverse mode will tend to propagate outside the active layer. We performed calculations of the optical confinement factor and the beam divergence by using the transfer matrix method. In our design, we use the concept of placing the waveguide layer outside the active region. This paper details the way to practical realization of such a novel device.