錳摻雜氮化鎵之載子動力學與自旋交換作用

Abstract

錳摻雜氮化鎵被認為是未來可在室溫操作的稀磁性半導體的最佳後選之一。但與錳摻雜砷化鎵不同的是，此材料的載子傳遞鐵磁性仍是一大爭論。在本研究中，我們藉由時間解析柯爾旋轉光譜量測電子的自旋生命期以及g因子，其在傳遞錳原子間的自旋資訊扮演了重要角色。當錳濃度增加後，電子自旋有生命期下降與g因子增加的現象。其中，g因子隨錳濃度線性增加的現象是由於電子在單位體積內與更多的錳原子作用所造成。透過擬合我們可得到s-d交換作用能N0α = 0.35 eV的結論。

Mn-doped GaN has been known as a promising candidate for dilute magnetic semiconductor (DMS) working at room-temperature. However, the carrier-mediate ferromagnetism is still under debate unlikely in Mn-doped GaAs. In this work, electron spin dynamics in GaN and Mn-doped GaN were investigated by time-resolved Kerr rotation (TRKR) spectroscopy, which plays an important role in transferring spin information between different Mn atoms. With the increasing Mn concentration, the electron spin shows a shorter lifetime and a larger g factor. In particular, the g factor exhibits a linear dependence on the Mn concentration, which is caused by interacting with more Mn atoms in unit volume. The s-d exchange energy N0α = 0.35 eV is determined by fitting procedure.