There are varied spin states in dilute magnetic semiconductors, and carriers are not the only elementary excitations that carry the spin. This article reports a study of spin interactions in excitons of ZnSe:NiI(II) nanostructures. High-quality ZnSe:NiI(II) nanobelts (NBs) prepared by chemical vapor deposition show a zinc blende structure by x-ray diffraction and Raman spectroscopy. The temperature-dependent photoluminescence spectra of doped NBs show independent free exciton (FX) and exciton magnetic polaron (EMP) peaks at room temperature with ferromagnetically coupled Ni ions. A single-mode lasing profile was obtained with femtosecond laser excitation due to condensation of EMPs over a threshold. The luminescence lifetimes at different pump powers indicated different relaxation profiles, confirming the formation of coherent EMP aggregates. At a slightly higher dopant concentration, a weak peak at the high-energy side of the FX peak showed up separately at low temperature; this should be the magnetic polaron emission band from the antiferromagnetically coupled Ni(II) pair binding with a FX (antiferromagnetic magnetic polaron). These results illustrate the typical spectroscopic characteristics of spin-spin magnetic coupling, exciton-spin or phonon interactions in dilute magnetic semiconductor nanostructures, showing that their different coupled spin types could work as exciton binders for their collective excitons, with possible use in spin nanophotonic devices and quantum modulations.

The optoelectronic properties and device absorption efficiencies of MoSO and MoSSe Janus monolayer have been investigated using the first‐principles calculations. It is revealed that the MoSO and MoSSe possess a semiconducting behavior with a bandgap of 1.61 eV (indirect) and 2.00 eV (direct), which is ideal for effective light absorption. The device absorption efficiency of the MoSO and MoSSe family has been calculated for the first time and it is found that this family has strongest absorption (90%) ranging from infrared to ultraviolet region of the light spectrum. Furthermore, they are an ideal contender for the top cell in tandem design due to their broader bandgap and high device absorption efficiency. This family also keeps a suitable band edge alignment with the water redox potentials. Thus, strong absorption efficiency and desirable photocatalytic property for splitting water make MoSO and MoSSe an efficient candidate for optoelectronic devices, photocatalysis, and solar cell applications.

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In order to meet the requirement of spintronic and optoelectronic, we have systematically investigated the effect of Mn doping and co-doping of Mn with C on the electronic, magnetic and optical properties of wurtzite zinc sulfide (ZnS) using first principle calculations. Our results find that single Mn doping alters the non-magnetic ZnS to a magnetic one and keeps its semiconducting and a semiconductor to half-metal transition is observed for Mn-C co-doping. Furthermore, an antiferromagnetic (AFM) and ferromagnetic (FM) ground states are favorable for Mn-doped and Mn-C co-doped system, respectively. Additionally, the optical properties of our studied configuration have been calculated in terms of real and imaginary parts of the complex dielectric function, absorption coefficient, and reflectivity. The absorption edge shifts slightly toward lower energy and intensity of the main peak become weak for single Mn doping, and a sharp peak at low energy is observed for the Mn-C co-doping. The analysis of optical absorption of Mn ions doped system shows the blue-and red-shifts of the d-d transition in the AFM and FM coupled of Mn ions doped configuration, respectively which is in good agreement with the experimental observations. The improved magnetic and optical properties of Mn-C co-doped ZnS shed light on the future application of such kind of materials in spintronic and optoelectronic devices such as remote sensing and photovoltaics.

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