In this work, the frequency response of a single-element, direct band gap indium gallium arsenide (In0.53Ga0.47As)
infrared photo-detector on a lattice matched indium phosphide (InP) substrate is investigated by varying the intrinsic
layer doping concentration. The intrinsic device operation and transport physics are theoretically determined and
simulated. The epitaxial layer structure, physical dimensions, doping profiles and carrier concentrations are modelled for
a complete PIN photodetector with cut-off wavelength of 1680 nm at 295 K. The calculated and simulated device
performance parameters are based on the responsivity, quantum efficiency, dark-current in reverse-biased operation,
frequency bandwidth and intrinsic junction capacitance. These parameters are also measured and the frequency response
is determined by a low-power 1064 nm neodymium-doped yttrium aluminium garnet (Nd:YAG) pulsed laser at the
output of a high-gain transimpedance amplifier. The shortest measurable pulse rise-time for this configuration is 12.4 ns.
The dark-current, frequency response and intrinsic junction capacitance results are used to represent the equivalent
circuit model of the photodetector at the input of the transimpedance amplifier. The primary goal is to identify the
variations in performance based on the intrinsic layer composition, manufacturing considerations and epitaxial
enhancements to improve the bandwidth of such a device.