ИСТИНА

Nanocrystalline zinc oxide is a semiconductor with these unique properties. Zinc oxide is a material with a wide band gap (3.3 eV) and very high energy of the exciton (60 meV), which makes it a promising material for high-efficiency light-emitting devices in the UV and visible range. The main problem is the difficulty to create LEDs and lasers based on ZnO material with the stable p-type conductivity. The reason for this lies in the predominance of intrinsic defects of donor type and acceptor in zinc. We have used the EPR technique for our investigations because it is sensitive to the detection of defects and interactions. In undoped zinc oxide the concentration of donor defects is located at 1017 cm-1 and the acceptor defects - at 1015 cm-1 [1]. An oxygen vacancies (VO) and zinc atoms in the interstices (Zni): were treated as a major donor in ZnO. Theoretical calculations have shown that Zni is a small donor (with low energy of activation) and VO is a deep defect. It was experimentally confirmed by electron paramagnetic resonance (EPR) [2]. Thus, the oxygen vacancies cannot contribute significantly to the conductivity. In this work the nature of defects (also known as paramagnetic centers) was identified. We observed several samples, which were prepared using different kind of technique. The obtained results can be useful for optics and LEDs/lasers applications in different systems. The experiments were performed using the facilities of the Collective Usage Center at Moscow State University.