Enhanced Curie temperature of InMnP:Zn—TC∼300K

Abstract

P -type bulk InP was prepared by the liquid encapsulated Czochralski method and subsequently diffused with Mn by heat treatment after the evaporation of Mn on top of InP:Zn using a molecular beam epitaxy system. The characteristics of Mn-diffused InMnP:Zn were investigated by an energy dispersive x-ray spectroscopy, photoluminescence, and a superconducting quantum interference device magnetometer measurements. The samples were characterized by transmission electron microscopy and no evidence of secondary phase formation of InMnP:Zn was found. The results of energy dispersive x-ray peak displayed injected concentration of Mn near 3%. The results of photoluminescence measurement showed that optical broad transitions related to Mn appeared around 1.2eV and it was confirmed that the transitions around 1.2eV were Mn-related band by the diffusion of Mn into InP:Zn. Clear ferromagnetic hysteresis loops were observed at 10 and 300K and the temperature-dependent magnetization showed ferromagnetic behavior around 300K, which is caused by carrier-mediated ferromagnetism in InMnP:Zn. It is found that a ferromagnetic semiconductor at room temperature can be formed in diluted magnetic semiconductor based on GaMnN and InMnP additionally co-doped with Mg and Zn, respectively.

Diluted magnetic semiconductor of p-type InMnP:Zn epilayer

“…With an increase in the annealing temperature to 600 1C for 60 s, together with most of the peaks of the as-grown epilayer, a broad band related to Mn appeared and shifted to lower energy of 1.187 eV which is known to be the typical energy position of Mn [13]. We observed a similar transition at 1.185 eV in unintentionally doped n-type InP bulk implanted with various doses (5 Â 10 12 -5 Â 10 16 cm À2 ¼ 10%) of Mn [14] and also observed transitions around 1.2 eV in p-type InP bulk doped with Mn near 3.0% [15]. A range of binding energies from 0.14 to 0.40 eV for the Mn center were reported [16].…”

“…A range of binding energies from 0.14 to 0.40 eV for the Mn center were reported [16]. The broad peaks at 1.187, 1.198, and 1.227 eV appear to arise from recombination of free electrons or electrons bound to donors with holes bound at a state which is at the energies of 0.233, 0.217, and 0.193 eV above the valence band edge in terms of an energy level scheme for Mn, namely peak at 1. were observed in p-type InP bulk doped with Mn near 3.0% [15].…”

“…Therefore, it is found that in this system the proper annealing temperature is 450 1C. p-type InMnP:Zn epilayers represent an enhanced ferromagnet (H c ¼ 311 G, saturation magnetization M ¼ 7:6 Â 10 À5 emu) in comparison with InMnP:Zn bulk (H c ¼ 134 G, M ¼ 4:1 Â 10 À5 emu) [15].…”

Enhanced Curie temperature persisting between 100 and 200K (∼50K by theory) with Mn (∼0.290%) based on InMnP:Zn

“…The papers of DMS based on InMnP with the same zinc blend structure as GaAs were also very recently reported, but focused on confirming whether ferromagnetism based on InMnP can be actually formed or not. Consequently, the ferromagnetism has been obtained [13][14][15], but further exact, physical ARTICLE IN PRESS www.elsevier.com/locate/jcrysgro 0022-0248/$ -see front matter r …”

Curie temperature in InMnP and the mechanism of phase transition

“…It is reported that InMnP treated with various methods by the implantation of Mn and the thermal diffusion of Mn has the same tendency of temperature dependence. In addition, the study of p-type InMnP:Zn co-doped with Zn(2.1-2.2 Â 10 18 cm À3 ) was investigated [13]. Mn was evaporated on the top of (1 0 0) InP:Zn co-doped with Zn using molecular beam epitaxy (MBE) system.…”