Peripheral photoresponse of a large p-n junction in a thick semiconductor

Two approximate analytic methods are given for deriving the laterally collected photocurrent in a mesa diode all of whose dimensions are large compared to the minority carrier diffusion length in the surrounding semiconductor, whose thickness is also large by comparison with the diffusion length. The better of these methods yields a laterally collected photocurrent equal to 0.53 times that of a thin-film device, in excellent agreement with the exact result of 0.50 derived by numerical techniques.