In this letter we outline our results on a new type of high‐speed photodetector [E. Gregor et al., Appl. Phys. Lett. 65, 2223 (1994)]. The device is based on the hybridization of a metal‐semiconductor‐metal photodetector and a p‐i‐n photodiode. The advantage of the device, which operates in the transit‐time limited regime, is that it removes the hole current from the high‐speed circuit through a third contact, and hence, increases the response speed of the device. In contrast to the previously published work [E. Gregor et al., Appl. Phys. Lett. 65, 2223 (1994)] we have used an excitation pulse that is much faster than the device response in order to fully investigate the effect of the third contact. We observe significantly more effect on the response once the third contact is connected with a subsequent increase of device response speed with increasing application of bias to this third contact. © 1996 American Institute of Physics.