<p>This work develops a theoretical model describing photothermal–acoustic wave propagation in laser-excited semiconductors by simultaneously incorporating quantum carrier transport and thermal memory effects. The classical photo-thermoelastic formulation is extended through a density-gradient (Bohm potential) correction in the carrier diffusion equation and a time-fractional heat conduction law that accounts for finite thermal relaxation. The resulting coupled system links elastic motion, carrier dynamics, and non-Fourier thermal transport within a consistent continuum framework suitable for nanoscale excitation regimes. Using normal-mode analysis combined with Laplace transform techniques, dispersion relations and attenuation characteristics of the coupled modes are obtained and physically classified. Numerical evaluation for silicon parameters shows that fractional thermal memory delays heat diffusion and sharpens the thermal wavefront, while quantum carrier pressure reduces localization of carrier and stress fields. Their combined action modifies phase velocity, penetration depth, and damping behavior compared with the classical photo-thermoelastic prediction. The model therefore explains why conventional diffusion-based theories overestimate energy localization under laser excitation and demonstrates the importance of accounting for both memory-dependent heat transport and quantum carrier spreading in micro- and nano-scale semiconductor devices such as photodetectors and surface acoustic wave sensors.</p>