Effects of Hydrogen Plasma Treatment on the Electrical and Optical Properties of ZnO Films: Identification of Hydrogen Donors in ZnO

Wurtzite ZnO has many potential applications in optoelectronic devices, and the hydrogenated ZnO exhibits excellent photoelectronic properties compared to undoped ZnO; however, the structure of H-related defects is still unclear. In this article, the effects of hydrogen-plasma treatment and subsequent annealing on the electrical and optical properties of ZnO films were investigated by a combination of Hall measurement, Raman scattering, and photoluminescence. It is found that two types of hydrogen-related defects, namely, the interstitial hydrogen located at the bond-centered (H-BC) and the hydrogen trapped at a O vacancy (H-O), are responsible for the n-type background conductivity of ZnO films. Besides introducing two hydrogen-related donor states, the incorporated hydrogen passivates defects at grain boundaries. With increasing annealing temperatures, the unstable H-BC atoms gradually diffuse out of the ZnO films and part of them are converted into H-O, which gives rise to two anomalous Raman peaks at 275 and 510 cm(-1). These results help to clarify the relationship between the hydrogen-related defects in ZnO described in various studies and the free carriers that are produced by the introduction of hydrogen.

cryptanalysis of the end-to-end security protocol for mobile communications with end-user identification/authentication

IEEE Computer Society

IDENTIFICATION OF THE ENERGY-LEVELS OF SI-RH

Two thermostable levels E(0.31) and E(0.58) related to Rh in Si were observed using deep level transient spectroscopy and double correlation deep level transient spectroscopy techniques. By means of thermal annealing and electron irradiation, the microscopic natures of these levels were identified for the first time. The levels E(0.31) and E(0.58) arise from by the same impurity center but have different charge states. Their microstructures are not related to a pure substitutional Rh atom, but correspond to a complex. This result is compared to our self-consistent theoretical calculation.

Architecture research and hardware implementation on simplified neural computing system for face identification

This paper describes a special-purpose neural computing system for face identification. The system architecture and hardware implementation are introduced in detail. An algorithm based on biomimetic pattern recognition has been embedded. For the total 1200 tests for face identification, the false rejection rate is 3.7% and the false acceptance rate is 0.7%.