Strain Effects on Rashba Spin‐Orbit Coupling of 2D Hole Gases in GeSn/Ge Heterostructures

Abstract

A demonstration of 2D hole gases in GeSn/Ge heterostructures with a mobility as high as 20 000 cm2 V−1 s−1 is given. Both the Shubnikov–de Haas oscillations and integer quantum Hall effect are observed, indicating high sample quality. The Rashba spin‐orbit coupling (SOC) is investigated via magneto‐transport. Further, a transition from weak localization to weak anti‐localization is observed, which shows the tunability of the SOC strength by gating. The magneto‐transport data are fitted to the Hikami–Larkin–Nagaoka formula. The phase‐coherence and spin‐relaxation times, as well as spin‐splitting energy and Rashba coefficient of the k‐cubic term, are extracted. The analysis reveals that the effects of strain and confinement potential at a high fraction of Sn suppress the Rashba SOC caused by the GeSn/Ge heterostructures.

Carrier Recombination Dynamics of Surface-Passivated Epitaxial (100)Ge, (110)Ge, and (111)Ge Layers by Atomic Layer Deposited Al2O3

“…Group-IV materials (i.e., Ge, GeSn, SiGeSn, SiGe) exhibit a potential application in line with quantum science and technology, due to their unique spintronic and optoelectronic functionalities valuable for qubits. − By exploiting strain and bandgap engineering of these materials via intelligent buffer engineering − and precise control of tin (Sn) composition in GeSn or SiGeSn during materials synthesis, ,,− , it will offer widespread applications in Si-compatible photonics and quantum technology, provided that one could synthesize device-quality group-IV materials. In addition, downscaling of silicon (Si) transistors was possible by changing the device geometry from planar to fin field effect transistors (FinFETs).…”

Isothermal Heteroepitaxy of Ge1–xSnx Structures for Electronic and Photonic Applications

“…9,10 To further enhance the SOC strength, materials with higher atomic numbers are preferred due to larger atomic potential variation, which is achieved by the incorporation of Sn atoms into Ge crystals. 11 Different from laser structures, which typically require thick layers and very large Sn contents, to widely separate the Γ and L-valleys of the conduction band, for electronic transport thin defect-free Ge 1−x Sn x layers or quantum wells (QWs) heterostructures are desirable. Such advanced heterostructures, which employ Ge or Si 1−x−y Ge y Sn x barrier layers to define Ge 1−x Sn x QWs, are extremely challenging for the epitaxial growth.…”

“…Furthermore, the Ge 1– x Sn x material system is making its way into a diversity of research fields, such as nanoelectronics, thermoelectrics, spintronics, and quantum computing . Due to their strong spin–orbit coupling (SOC), holes in Ge have emerged as one of the most promising spin qubit candidates. , To further enhance the SOC strength, materials with higher atomic numbers are preferred due to larger atomic potential variation, which is achieved by the incorporation of Sn atoms into Ge crystals …”

“… 9 , 10 To further enhance the SOC strength, materials with higher atomic numbers are preferred due to larger atomic potential variation, which is achieved by the incorporation of Sn atoms into Ge crystals. 11 …”

CMOS Beyond Silicon: Vertical GeSn Nanowire MOSFETs

“…This property was recently exploited leading to breakthrough results in photonics, like optically and electrically driven GeSn lasers and mid-infrared imagers integrated on Si [31][32][33] . Furthermore, pioneering works on spin-orbit coupling, spin transport 34 and thermoelectric properties 35 of GeSn underline the potential of such alloys. In addition to their unprecedented electro-optical properties, a major advantage of GeSn binaries is also that they can be grown in the same epitaxy reactors as Si and SiGe alloys, enabling an all-group IV optoelectronic semiconductor platform that can be monolithically integrated on Si.…”