Fabrication Of P-type ZnO Thin Films Via MOCVD Method By Using Phosphorus As Dopant Source

ZnO is a novel Ⅱ—Ⅵ compound semiconductor with a 3.37eV room-temperature direct band gap. Researches indicate that n-type ZnO films can be well prepared, however, due to the high self-compensating process on doping derived from the intrinsic donor defects such as oxygen vacancy (V_O) and zinc interstitial (Zn_i) atoms, ZnO is formed n-type naturally and p-type ZnO is difficult to prepare. How to realize p-type ZnO films through doping is the key step for application in the fields of ZnO-based optoelectronic devices, in which great progresses are being made now.Phosphorus-doped ZnO thin films have been grown by metalorganic chemical vapor deposition. In our experiment, diethylzinc (DEZ) was used as Zn precursor, and O₂ gas and P₂O₅ power were used as oxidizing and phosphorus doping sources, respectively. The properties of obtained ZnO films were examined by X-ray Difrfraction (XRD), Hall-effect measurement, transmission spectra, photoluminescence spectra, second ion mass spectra(SIMS) and energy dispersive spectra(EDS).The results showed that the P doped ZnO films can be realized at the substrate temperature of 400℃ and 450℃ with a p-type conduction .At the temperature of 420℃,we obtained a high quality p-type ZnO:P film,1ft 1such as resistivity of 4.46￡2cm, carrier density of 1.61x10 cm , Hall mobility of 0.838cm2/V.s. The p-type ZnO film had a transmittance about 90% in visible region, and had good optical properties in photoluminescence spectra. Meanwhile, the obtained ZnO:P films were also annealed under differenet conditions. Results indicated that acceptor could be activated under certain condition, and p-type ZnO films can be obtained through annealing.