Materials with crystal structures containing tetrahedral motifs are preferable for optoelectronic applications because they often have direct band gaps and low electron effective masses. However, crystal structures of manganese chalcogenides typically contain octahedral motifs, such as in rock salt (RS) MnS and MnSe materials. Here, we experimentally show that MnS1−xSex alloys with tetrahedrally bonded wurtzite (WZ) structure can form between MnSe and MnS parent compounds with octahedral RS structures, at S-rich compositions (x < 0.4) and low synthesis temperatures (∼300 °C). The calculated mixing enthalpies of MnS1−xSex alloys in RS and WZ structures cannot explain this experimental observation, so we hypothesize that WZ stabilization may be related to smaller structure density and lower surface energy compared with RS. The resulting WZ MnS1−xSex alloys have 3.0–3.2 eV optical absorption onset and lower electrical conductivity (<0.0001 S/cm) than the parent RS compounds. These experimental measurement results are consistent with computationally predicted band gaps and effective masses.

Beta-gallium oxide (β-Ga2O3) is of increasing interest to the optoelectronic community for transparent conductor and power electronic applications. Considerable variability exists in the literature on the growth and doping of Ga2O3 films, especially as a function of growth approach, temperature, and oxygen partial pressure. Here pulsed laser deposition (PLD) was used to grow high-quality β-Ga2O3 films on (0001) sapphire and (−201) Ga2O3 single crystals and to explore the growth, stability, and dopability of these films as function of temperature and oxygen partial pressure. There is a strong temperature dependence to the phase formation, morphology, and electronic properties of β-Ga2O3 from 350 to 550 °C.