Numerical investigation of monolithic heterojunction and buried layer GaAs lateral p-i-n photodetectors

This paper presents a numerical study of two planar photodetector device designs, a heterojunction lateral p-i-n and a buried layer lateral p-i-n. The devices are planar structures comprised of interdigitated p(+) and n(+) wells containing either a heterojunction or buried charge sheet. Numerical simulation reveals that when pulsed with an 827 nm optical source at 0.68 mW/cm(2), these two devices exhibited vastly superior frequency performance and responsivity compared to a heterostructure metal-semiconductor-metal photodetector formed with identical finger spacing and geometry. The calculated dark currents are similar in magnitude while the capacitances vary among the devices. (C) 1999 American Institute of Physics. [S0021-8979(99)05305-0].