MBE growth and characterization of Zn1-xCrxTe diluted magnetic semiconductor

Abstract

Cr doped ZnTe (Zn1-xCrxTe) diluted magnetic semiconductor thin films were prepared on GaAs [001] substrates at low temperature by solid-source molecular beam epitaxy (MBE) growth. Growth conditions were optimized to be with Zn/Te flux ratio from 1.2 to 1.4 and substrate temperature of 200oC. Cr doping concentration was varied by changing the Cr K-cell temperature. Samples with Cr concentration from 0.026 to 0.14 were grown and the Cr concentration was determined by particle induced X-ray emission (PIXE). The Curie temperature was determined to be 158K with x = 0.026, 185K with x=0.035 and 265K with x=0.14, respectively. Highly Cr doped sample with strong magnetization and Tc ~ 365K was grown. However, no Zn element was found through Auger electron spectroscopy (AES) measurement. We suggest monoclinic Cr3Te4 could be responsible for the strong ferromagnetism observed because the similar properties observed for our sample and the literature.