Principal issues in producing new ultraviolet light emitters based on transparent semiconductor zinc oxide

Electrochemical growth of n-ZnO onto the p-type GaN substrate: p-n heterojunction characteristics

“…This is due to the advance properties of ZnO possess, such as having a wide bandgap, high exciton binding energy ͑60 meV͒, high quality bulk single crystal, high radiation tolerance, compared to the other classical, InP, GaAs, Si, and wide bandgap, GaN, ZnS, ZnSe, semiconductor materials. [1][2][3] In order to reach high quality optoelectronic device with an active layer ZnO, one of the main obstacles should be solved, namely, p-type conductivity, 4 which is still a problem in obtaining high quality and stable p-type conductivity, although recently many p-type and p-n homojunction structures have been reported. [4][5][6][7][8] It encourages the researchers to investigate ZnO heterojunction structures, especially, after ultraviolet emission has been achieved on a simple p-Si/ n-ZnO heterojunction.…”

ZnO/ZnMgO: cubic quantum well laser in UV spectrum

“…The essential phase of crystallization for ZnO is hexagonal wurtzite phase [21]. Theoretical [22] and experimental [23][24][25] studies have been focused on ZnO, with an interest to study the properties of ZnO in its cubic phase [26].…”

Stimulated electroluminescence emission from n-ZnO/p-GaAs:Zn heterojunctions fabricated by electro-deposition

“…In spite of much progress in forming ZnO material, it is hard to achieve high quality and reproducible p-ZnO. Because unintentional defects such as oxygen vacancies (V o ) and zinc interstitials (Zn i ) result in shallow donor levels, 9 ZnO naturally exhibits n-type conductivity due to this intrinsic donor type defects, and obtaining p-type ZnO remains as a major problem to be solved. For this reason, n-type ZnO growth on the available and comparable p-type materials could provide an alternative way to present the advantages of ZnO.…”