Narrow Base Germanium Photodiodes

摘要: The operation of germanium photodiodes at room temperature both as reverse-biased and photovoltaic detectors is analyzed. This analysis takes into account generation hole-electron pairs in the base an exponentially decreasing function distance from surface. General expressions are derived for steady-state time-varying detector signal components. intrinsic frequency behavior (that associated with carrier diffusion point to p-n junction) same operation. frequency-cutoff compared that a homogeneous transistor and, case small loss photogenerated carriers by surface recombination, it shown cutoff frequencies essentially identical width. Photodiodes may be useful modulating well above this if radiation penetrating since type response does not decrease rapidly cutoff. equivalent circuits obtained noise-equivalent circuit It where 1/f noise neglected, most small-signal applications greatly superior With reduction width will increased, bulk recombination decreased, capacitance junction reduced. Thus, improvements realized.