Image sensor with electron and hole collection electrodes

Imaging apparatus, comprising:

• a photosensitive medium configured to convert incident photons into pairs of electrons and holes;
• and
• an array of pixel circuits formed on a semiconductor substrate, each pixel circuit defining a respective pixel and comprising:
• an electron-collecting electrode in contact with the photosensitive medium at a first location in the pixel;
• a hole-collecting electrode in contact with the photosensitive medium at a second location in the pixel,
• wherein the electron-collecting electrode and the hole-collecting electrode extend through the photosensitive medium;
• and
• circuitry coupled to apply a positive potential to and collect the electrons from the electron-collecting electrode and to apply a negative potential to and collect the holes from the hole-collecting electrode and to output a signal indicative of an intensity of the incident photons responsively to the collected electrons and holes.

Imaging apparatus, comprising:

• a photosensitive medium configured to convert incident photons into pairs of electrons and holes;
• and
• an array of pixel circuits formed on a semiconductor substrate, each pixel circuit defining a respective pixel and comprising:
• an electron-collecting electrode in contact with the photosensitive medium at a first location in the pixel;
• a hole-collecting electrode in contact with the photosensitive medium at a second location in the pixel;
• and
• circuitry coupled to apply a positive potential to and collect the electrons from the electron-collecting electrode and to apply a negative potential to and collect the holes from the hole-collecting electrode and to output a signal indicative of an intensity of the incident photons responsively to the collected electrons and holes,
• wherein the circuitry is configured to collect the holes with a first conversion gain and to collect the electrons with a second conversion gain, which is different from the first conversion gain, and to output the signal with a dynamic range that is enhanced responsively to a relation between the first and second conversion gains.

A method for imaging, comprising:

• coupling an array of pixel circuits formed on a semiconductor substrate to a photosensitive medium configured to convert incident photons into pairs of electrons and holes, each pixel circuit defining a respective pixel and comprising an electron-collecting electrode in contact with the photosensitive medium at a first location in the pixel and a hole-collecting electrode in contact with the photosensitive medium at a second location in the pixel;
• applying in each pixel a positive potential to the electron-collecting electrode and a negative potential to the hole-collecting electrode;
• collecting in each pixel the electrons from the electron-collecting electrode and the holes from the hole-collecting electrode, and outputting a signal indicative of an intensity of the incident photons responsively to the collected electrons and holes;
• and
• overlaying a common electrode, which is at least partially transparent, on the photosensitive medium, and biasing the common electrode at a voltage between the positive potential applied to the electron-collecting electrode and the negative potential applied to the hole-collecting electrode.