Ultra-Wide-Band-Gap Semiconductor Optical Switches and Photodetectors

A photoconductive switching circuit comprising:

• a semiconductor having a bandgap of at least 2 eV and doped with chemical dopants that impart visible responsivity to the semiconductor;
• metal electrodes fabricated on the semiconductor in such a way that at least one of the metal electrodes is a rectifying junction;
• a voltage source, electrically connected to the metal electrodes, to apply a bias voltage across the metal electrodes;
• a light source, in optical communication with the semiconductor, to illuminate the semiconductor with light having a photon energy less than the bandgap of the semiconductor, the light causing the semiconductor to conduct current between the metal electrodes under the bias voltage;
• and
• a bias pulse generator, electrically connected to the metal electrodes, to apply a transient voltage pulse with a polarity opposite the bias voltage to the metal electrodes, the transient voltage pulse suppressing persistent photocurrent in the semiconductor.

A method of detecting light having a photon energy less than a bandgap of AlN with a photodetector comprising a pair of metal electrodes on an AlN layer doped with chemical dopants forming deep defects, at least one of the pair of metal electrodes forms a rectifying junction with the AlN layer, the method comprising:

• applying a bias voltage across the pair of metal electrodes;
• while applying the bias voltage, illuminating the AlN layer with the light, the deep defects at the rectifying junction absorbing the light;
• and
• measuring a change in conductance of the rectifying junction caused by absorption of the light by the deep defects.