The noise matrix of low frequency (up to 10 kHz) shot noise associated with the photocurrent generated in double-Schottky-barrier structure has been proposed based on its simplified model. It has been shown that the noise matrix developed can be applicable not only to planar metal-semiconductor-metal double-Schottky-barrier structures under optical illumination but also to the existing simple shot noise theory. Representation of the noise matrix is informative, in particular, as to the crosscorrelation between any two current components contributing to the noise of the device. (C) 2003 Elsevier Science Ltd. All rights reserved.