Patent ID: 8138567

Claim:
An optically sensitive device comprising: a first contact and a second contact, each having a work function; an optically sensitive material between the first contact and the second contact, the optically sensitive material comprising a N-type semiconductor, and the optically sensitive material having a work function; circuitry configured to apply a bias voltage between the first contact and the second contact; the magnitude of the work function of the optically sensitive material being at least 0.4 eV less than the magnitude of the work function of the first contact, and also at least 0.4 eV less than the magnitude of the work function of the second contact; the optically sensitive material having a hole lifetime that is greater than the hole transit time from the first contact to the second contact when the bias is applied between the first contact and the second contact; the first contact providing injection of holes and blocking the extraction of electrons; and the interface between the first contact and the optically sensitive material providing a surface recombination velocity less than 1 cm/s.