Theoretical analysis of confined quantum state GaAs/AlGaAs solid-state photomultipliers

A detailed theoretical analysis of the design considerations of a solid-state photomultiplier based on avalanche multiplication of carriers out of confined quantum states is presented. Since these devices are unipolar, much lower noise and higher speed of performance are anticipated as compared with interband avalanche photodiodes. As an example of the design criteria for confined-state photomultipliers, a GaAs/Al_0.32Ga_0.68As multiquantum well structure is analyzed as to impact ionization rate, gain, dark current, and multiplied dark current. It is found that the highest gain is achieved in an asymmetric quantum well structure in which the second barrier height is half as large as the initial barrier height. The gain is further evaluated for a symmetric quantum well device. The effects of the applied electric field, quantum well doping concentration, and layer widths on device performance are examined