A Photonic Atom Probe Study of Thermal Effects at the Nanosecond and Nanometer scale

The thermal effect of a subpicosecond laser pulse impinging on a nanoscale semiconductor structure is evaluated by analyzing the photoluminescence (PL) from samples characterized in situ by atom probe tomography. By examining time-resolved PL and ion time-of-flight spectra, we establish the correct time scale of transient processes─carrier recombination and carrier-phonon scattering─following a laser pulse. This approach allows for analysis of peak energies and bandwidths from temperature- and laser intensity-dependent PL spectra, enabling the estimation of an effective temperature within a few hundred picoseconds after the laser pulse. The analysis was conducted on ZnO/(Mg,Zn)O quantum well heterostructures, where the results can be readily interpreted using ZnO's specific heat capacity and its temperature dependence.