High Curie Temperature Ferromagnetism and High Hole Mobility in Tensile Strained Mn‐Doped SiGe Thin Films

Abstract

Diluted magnetic semiconductors based on group‐IV materials are desirable for spintronic devices compatible with current silicon technology. In this work, amorphous Mn‐doped SiGe thin films are first fabricated on Ge substrates by radio frequency magnetron sputtering and then crystallized by rapid thermal annealing (RTA). After the RTA, the samples become ferromagnetic semiconductors, in which the Curie temperature increases with increasing Mn doping concentration and reaches 280 K with 5% Mn concentration. The data suggest that the ferromagnetism comes from the hole‐mediated process and is enhanced by the tensile strain in the SiGe crystals. Meanwhile, the Hall effect measurement up to 33 T to eliminate the influence of anomalous Hall effect reveals that the hole mobility of the annealed samples is greatly enhanced and the maximal value is ≈1000 cm2 V−1 s−1, owing to the tensile strain‐induced band structure modulation. The Mn‐doped SiGe thin films with high Curie temperature ferromagnetism and high hole mobility may provide a promising platform for semiconductor spintronics.

Structure-dependent high-TC ferromagnetism in Mn-doped GeSe

“…The Mn 2p peaks are distributed around 641.89 eV and 652.73 eV, corresponding to Mn 2+ state. 20 Notably, the binding energies of Ge 0 and Ge 4+ states (28.92 eV and 32.84 eV), and Mn 0 , Mn 3+ and Mn 4+ states (638.45 eV, 640.46 eV and 642.23 eV) 30,35–37 are not observed in our samples. The results indicate that GeMnSe compounds are successfully synthesized and substitutional Mn 2+ ions are doped in the GeSe lattice.…”

“…27,28 The two peaks are blue-shifted with increasing the Mn concentration, owing to the increase of lattice constant caused by incorporation of Mn dopants with an atomic radius (1.61 Å) larger than that of Ge in the GeSe lattice. 29,30 Another small peak at 175.2 cm −1 exists in all the samples, which is corresponding to the A g 2 vibrational mode related to V Ge s in GeSe. 31 In addition, the peak at 258.7 cm −1 , which is attributed to the phonon vibrations of V Ge -induced Se chains and Ge–Se bonds, 32–34 dramatically decreases or even disappears after Mn doping, indicating that V Ge s are mainly occupied by Mn dopants.…”

Спонтанный спиновый магнетизм донорных электронов проводимости гибридизированных состояний кристалла, образованных системой примесных атомов 3d-элементов низкой концентрации (<1 at.%)

“…Итоговый, впервые в полном объеме представленный результат относится к области физики спонтанного примесного магнетизма полупроводниковых кристаллов. Известные исследования в этой области сосредоточены на реализации магнитного упорядочения при достаточно высокой концентрации 3d-примесей ∼ (3−9) at.% и основаны на представлении о том, что спонтанная спиновая поляризация примесной электронной системы возникает благодаря межпримесному взаимодействию, которое обеспечивает взаимную спонтанную поляризацию ионных остовов примесных атомов [1][2][3].…”

Half-Metallicity and Magnetic Anisotropy in Transition-Metal-Atom-Doped Graphitic Germanium Carbide (g-GeC) Monolayers

“…Magnetic properties induced by vacancy defects, substitution doping, adsorption, edge effects, applied strain, and electric field in 2D materials have been extensively studied. − In particular, the use of transition-metal atom (TM)-doped semiconductor is at a fairly mature stage, both theoretically and experimentally. − Here, TMs serve as a source of spin or free charge in nonmagnetic semiconductors. For example, studies have shown that TM-doped 2D materials such as graphene, phosphorene, MoS 2 , and In 2 Se 3 monolayers provide valuable information on the properties of diluted magnetic semiconductors. − The Mn-atom-doped SiGe thin film is successfully prepared and shows high T C (280 K) and high hole mobility (1003 cm 2 /(V s)) …”

“…24−33 The Mn-atom-doped SiGe thin film is successfully prepared and shows high T C (280 K) and high hole mobility (1003 cm 2 /(V s)). 34 The g-GeC monolayer is an important group IV binary compound that is widely used in heterostructure devices and solar cells due to its narrow optical band gap. 11 It is reported that g-GeC has a stable 2D honeycomb structure and a direct band gap.…”