Magnetic Iron Implanted CuInSe2 Thin Film - a Possible Room Temperature Diluted Magnetic Semiconductor with Smallest Bandgap
Li-Jung Liu1, Chih-Hao Lee1*, Yu-Sheng Chen1
1Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan
* presenting author:Chih-Hao Lee, email:chlee@mx.nthu.edu.tw
Room temperature magnetic semiconductor is important for the applications of spintronics. However, most of them are wide bandgap materials. In this report, the electronic structure and magnetic properties of an iron ion implanted small bandgap CuInSe2 semiconductor thin film was studied. Room temperature ferromagnetic property was observed from the results of the SQUID measurement, which shows the sample has a ferromagnetic property. At low doping level, the zero-field and non-zero field cool measurements show two curves almost identical. The zero field cool and non-zero field cool experiments did not show any evidence of an existence of blocking temperature even down to 5 K, which implies no Fe clusters are formed. It could be a room temperature diluted magnetic semiconductor with smallest bandgap among all the diluted magnetic semiconductors. While at high doping level, these two curves only merged at the temperature slightly higher than the room temperature, which implies that at high doping level, the ferromagnetic property is originated from a cluster with the blocking temperature slightly higher than the room temperature. This result implies that at high doping level, the ferromagnetic property is originated from Fe clusters with the blocking temperature higher than the room temperature.



Keywords: diluted magnetic semiconductor, CuInSe2, ion implantation