Jianze Zhao

Realization of ultraviolet electroluminescence from ZnO homojunction with n-ZnO∕p-ZnO:As∕GaAs structure

ZnO homojunction light-emitting diode with n-ZnO∕p-ZnO:As∕GaAs structure is produced by metal organic chemical vapor deposition. The p-type ZnO:As film is obtained out of thermal diffusion of arsenic from GaAs substrate with subsequent thermal annealing at 550°C. The n-type layer is composed of unintentionally doped ZnO film. Desirable rectifying behavior is observed from the current-voltage curve of the ZnO p-n homojunction. Furthermore, two distinct electroluminescence bands centered at 3.2 and 2.5eV are obtained from the junction under forward bias at room temperature.

Electroluminescence from n-ZnO/p-ZnO : Sb homojunction light emitting diode on sapphire substrate with metal–organic precursors doped p-type ZnO layer grown by MOCVD technology

An n-ZnO/p-ZnO : Sb homojunction light emitting diode was fabricated on c-plane sapphire by metal–organic chemical vapour deposition (MOCVD). The p-type ZnO layer with a hole concentration of 1.27 × 1017 cm−3 was fabricated using trimethylantimony (TMSb) as the Sb doping source. The current–voltage characteristics of the device exhibited a desirable rectifying behaviour with a turn-on voltage of 3.3 V. Distinct electroluminescence with ultraviolet and visible emissions was detected from this device under forward bias at room temperature. Moreover, metal–organic source TMSb is an effective and controllable dopant in the MOCVD technique, which is suitable for further industrialized production.

Cu related doublets green band emission in ZnO:Cu thin films

Cu-doped ZnO (ZnO:Cu) thin films were grown on Si (111) substrate by low-pressure metal-organic chemical vapor deposition equipment. The crystal structures and optical properties of as-grown sample were examined. X-ray diffraction patterns indicated a lattice relaxation after the Cu doping. The incorporation of Cu atoms into ZnO film and its existence in a bivalent state were demonstrated by x-ray photoelectron spectroscopy measurements. Low-temperature photoluminescence was carried out at temperature of 11.4 K for both unintentionally doped and Cu-doped ZnO films. A characteristic green-luminescence with fine structure consisted of doublets emission peak was observed, which was believed to be associated with Cu doping. A theoretical model based on hydrogen analog has been proposed to explain this phenomenon. It provides new information about the detailed role of Cu in ZnO thin films.

Room temperature electroluminescence from the ZnO homojunction grown on an n+-Si substrate by metal–organic chemical vapor deposition

ZnO film was grown on a heavily phosphor-doped n+-Si substrate by metal–organic chemical vapor deposition technology. X-ray photoelectron spectroscopy measurements indicate that a two-layer structure, comprised of a phosphor-doped ZnO layer and an un-doped ZnO layer, was formed during the diffusion process of phosphor from the n+-Si substrate. The current–voltage characteristic exhibited significant rectifying behavior with low-leakage current for this device. The distinct defect-related blue–white electroluminescence was observed, the origin of which was confirmed to be from the ZnO p–n homojunction.

p-Type Sb-Doped ZnO Thin Films Prepared by Metallorganic Chemical Vapor Deposition Using Metallorganic Dopant

Reproducible p-type Sb-doped ZnO thin films were fabricated on c-plane sapphire substrates by the metallorganic chemical vapor deposition (MOCVD) technique using trimethylantimony as the doping precursor. Sb was introduced into ZnO thin films as a p-type dopant without any phase separation. Obvious donor-acceptor pair emissions were observed from photoluminescence spectra of ZnO:Sb films at 10 K. The acceptor binding energy is estimated to be ∼ 124 meV. Using the metallorganic source as the dopant of p-type ZnO thin films by the MOCVD technique is beneficial for the industrialized production of ZnO light-emitting diodes.