Role of energy partitioning on electron-hole recombination, trapping, and detection in silicon detectors

The dynamics of electron-hole pair creation and transport in a semiconductor control the fundamental signal response for radiation detection. Extensive studies on silicon detectors have led to contradictory interpretations on the origins of the pulse height defect (PHD) and nonlinear response. In this study, recombination and trapping behaviors of a controlled number of electron-hole pairs produced within different volumes along the ion path are investigated, and the pulse height generated is analyzed in terms of energy partitioning. The results clearly demonstrate that a high recombination rate is not observed for heavy ions; moreover, significant trapping associated with the atomic defects produced by individual ions is responsible for the nonlinear response at low energies and PHD at high energies.