Defects at nitrogen site in electron-irradiated AlN

電子線照射したAlN中の窒素格子位置の欠陥

Son, N. T.*; Gali, A.*; Szab, .*; Bikermann, M.*; 大島 武; 磯谷 順一*; Janzn, E.*

Son, N. T.*; Gali, A.*; Szab, .*; Bikermann, M.*; Oshima, Takeshi; Isoya, Junichi*; Janzn, E.*

耐放射線性にも優れるといわれる窒化アルミ(AlN)中に発生する照射欠陥に関しての知見を得るために、AlN試料に2MeV電子線を照射し、発生した欠陥を電子常磁性共鳴(EPR)により調べた。その結果、EI-1と名付けられたスピン1/2の欠陥中心が観測された。電子のスピンと囲まれる4つのAの核スピンとの超微細相互作用を詳細に調べ、さらに、スーパーセルを用いた理論計算結果と比較したところ、得られたEI-1中心はAlN中の中性の窒素空孔型の欠陥であると帰結できた。

AlN samples were irradiated with 2 MeV electrons, and defects in the AlN were measured using an electron paramagnetic resonance (EPR). As a result, a defect center, labeled EI-1, with an electron spin S=1/2 and a clear hyperfine hf structure was observed. The hf structure was shown to be the interaction between the electron spin and the nuclear spins of four A nuclei with the hf splitting varying between 6.0 and 7.2 mT. By the Comparison between the hf data obtained from EPR and supercell calculations, we concluded that the EI-1 defect is the best candidate for the neutral nitrogen vacancy in AlN.