This work covers the structure and optical characteristics of nanoscale semiconductor heterostructures under various circumstances including pressure and uniaxial strain, for use in medical research equipment and communications. In a heterostructure, the choice of materials and the bandgap of the materials are very important for making a lasing wavelength for a certain application. By using semiconductor alloys, quantum well structures, and applying pressure, temperature, or strain on semiconductor layers, one can modify the bandgap without altering the material. Typically, various semiconductor layers developed at the nanoscale on a GaAs, InP, or GaSb substrate are used for fabricating lasers. The main challenge in the fabrication, however, is to control the nanoscale layer thickness that is generated on the substrate. The anisotropy or isotropy phenomena and optical gain enhancements achieved in various QW-heterostructures under strain, pressure, and temperature changes are described in this paper. Changes in optical gain are correlated with changes in bandgap. Variations in bandgap offer an in-depth evaluation of several applications through frequency analysis, which can be employed in solar cells, LEDs, lasers, and biological imaging, among other applications.