Quantum dot infrared photodetectors (QDIP)

A method of converting light signals to electrical signals comprising:

• storing charge carriers in semiconductor quantum dots having zero-dimensional levels established by size and composition of the quantum dots and height of the confining potential of the barriers;
• exposing the quantum dots to electromagnetic radiation having sufficient energy to eject stored carriers from the quantum dot layers by photoemission;
• and
• applying a bias voltage across emitter and collector layers between which a series of quantum dot layers containing the quantum dots are located, separated by barriers, to cause the carriers ejected from the quantum dot layers by photoemission to flow to a collector, while replacing the ejected carriers from the quantum dot layers with carriers originating from an emitter.

A photodetector comprising:

• (a) multiple layers of quantum dots and a barrier separating each layer of quantum dots from an adjacent layer of quantum dots,
• (b) an emitter layer and a collector layer, and a corresponding barrier separating each of the emitter layer and collector layer from an adjacent layer of quantum dots on respective opposite ends of the multiple layers of quantum dots,
• (c) conductors for applying a bias voltage between the collector and emitter, and
• (d) means for allowing electromagnetic radiation to be exposed to at least some of the layers of quantum dots.