A review of recent research on the growth and physical properties of single crystal metastable elemental and alloy semiconductors

Several research groups have recently reported the growth of metastable semiconductors which were not only single phase but, in many cases, high quality single crystals. The systems reported to date include the (III–V)1−xIVx alloys (GaAs)1−xSix, (GaAs)1−xGex, and (GaSb)1−x Gex, the nonisostructural alloys Pb1−xCdxS, InSb1−xBix, and Ge1−xSnx, elemental α-Sn, and GaAs1−xSbx with x values within the miscibility gap. Several of these systems have been grown with compositions ranging across the pseudobinary phase diagram and have been found to exhibit good thermal stability against phase separation at temperatures ≥500 °C. In addition to crystal growth studies, structural, optical, electrical, lattice dynamic, and thermodynamic measurements have been carried out. These results are reviewed and an attempt is made to establish a foundation for understanding and modeling crystal growth of this new class of semiconducting materials.