Molecular Beam Epitaxy

18III‐Nitride Dilute Magnetic Semiconductors

Yi‐Kai Zhou^1,2 and Hajime Asahi²

¹Key Laboratory of Optoelectronic Material and Device, Mathematics & Science College, Shanghai Normal University, Shanghai 200234, China

²The Institute of Scientific and Industrial Research, Osaka University, 8‐1, Mihogaoka, Ibaraki 567‐0047, Osaka, Japan

18.1 Introduction

Dilute magnetic semiconductors (DMSs) are of great importance from the viewpoint of spintronics to control spins, charges and photons [1,2]. Examples of the semiconductor spintronic devices are tunnel magnetoresistance (TMR) devices, circular polarized laser diodes (CP‐LDs), and spin field effect transistors (FETs). For device application, it is very important that the Curie temperature (T_C) of DMSs should be higher than room temperature. It should also be based on a typical semiconductor in which the carrier control technique is well established. However, the highest Curie temperature for the established III–V‐based DMS GaMnAs was 200 K [3], far from room temperature.

A theoretical prediction was made by Dietl et al. [4] based on a mean field model. They reported that Mn‐doped GaN will exhibit T_C exceeding room temperature. Another theoretical study by first principles calculation was performed by Sato and Katayama‐Yoshida [5]. This showed that V‐, Mn‐, and Cr‐doped GaN are promising candidates as room‐temperature ferromagnetic DMSs, and that Cr‐doped GaN has the most stable ferromagnetic states.

Transition‐metal (TM) and rare‐earth (RE ...