What does an InGaAs detector sensitivity curve look like?
Indium gallium arsenide (InGaAs) is a compound semiconductor. Like a silicon photodiode, an InGaAs photodiode is a photovoltaic element that has a P-N junction. The band gap energy of InGaAs, however, is smaller than that of silicon, so it absorbs light of longer wavelengths. This means that InGaAs photodiodes are sensitive to wavelengths that exceed the range of silicon photodiodes. The graph displayed in this slide shows the spectral sensitivity characteristic of an InGaAs photodiode.