Temperature-Dependence of Ge on Si p–i–n Photodetectors

We investigate the temperature dependence of germanium on silicon p-i-n photodetectors in terms of both dark current density and near-infrared responsivity. The dark current increases by nearly a factor 1.6 every 10degC, consistently with carrier generation in the space charge region. The responsivity has a complex trend, its temperature variation depending on wavelength and on the germanium quality. Detectors with a large defect density in the active layer exhibit a reduced responsivity as the temperature increases.