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Electrical properties of nitrogen implanted GaSe single crystal

Parlak, Mehmet
Turan, Raşit
Akınoğlu, Bülent Gültekin
N-implantation to GaSe single crystals was carried out perpendicular to c-axis with ion beam of 6x10(15) ions/cm(2) dose having energy values 30 keV and 60 keV. Temperature dependent electrical conductivities and Hall mobilities of implanted samples were measured along the layer in the temperature range of 100-320 K. It was observed that N-implantation decreases the resistivity values down to 10(3) Omega-cm depending on the annealing temperature, from the room temperature resistivity values of as-grown samples lying in the range 10(6)-10(7)Omega-cm. The temperature dependent conductivities exhibits two regions (100-190 and 200-320 K) with the activation energies of 234-267 meV and 26-74 meV, for the annealing temperatures of 500 and 700 degreesC, respectively. The temperature dependence of Hall mobility for the sample annealed at 500 degreesC shows abrupt increase and decrease as the ambient temperature increases. The analysis of the mobility-temperature dependence in the studied temperature range showed that impurity scattering and lattice scattering mechanisms are effective at different temperature regions with high temperature exponent. Annealing of the samples at 700 degreesC shifted impurity scattering mechanism toward higher temperature regions. In order to obtain the information about the defect produced by N-implantation, the carrier density was analyzed by using single donor-single acceptor model. We found acceptor ionization energy as E-a = 450 meV, and acceptor and donor concentration as 1.3 x 10(13) and N-d = 3.5 x 10(10) cm(4), respectively.