Diluted Magnetic Semiconductors based on Cr-doped InN

Diluted magnetic semiconductors based on GaN have been widely studied following theoretical work that predicts room temperature ferromagnetism in these materials. However, there have been no reports yet of InN-based DMS materials. Here, we have studied the InN system doped with Cr and Mn. The films were grown on c-plane sapphire substrates by Plasma- Assisted MBE using a MOCVD-grown GaN buffer layer. X-Ray Diffraction rocking curve measurements confirmed single crystalline orientation with the FWHM of InN (0002) X-Ray rocking curve about 0.1\r{ }. PL measurements revealed a room-temperature bandgap of 0.8 eV and Hall measurements yield an n-type carrier concentration of about 5*10$^{19 }$cm$^{ -3}$ in both undoped InN as well as Cr-doped InN. While XRD measurements of the Mn-doped films reveal secondary phase formation, the Cr-doped films show no evidence of the formation of compounds such as CrN or Cr$_{2}$N. Magnetic measurements were made on the films using superconducting quantum interference device (SQUID) magnetometry. While the Cr-doped films show a clear magnetic hysteresis as well as remanence up to 300K, the Mn-doped films have less clear magnetic properties. Thus we present evidence of ferromagnetism in n-type, Cr-doped InN.