Reduced dark current photodetector

A photo-detector, comprising:

• a photo absorbing layer comprising an n-doped semiconductor exhibiting a valence band energy and a conducting band energy;
• a barrier layer exhibiting a thickness, a first side of said barrier layer adjacent a first side of said photo absorbing layer;
• and
• a contact layer comprising a doped semiconductor, said contact layer being adjacent a second side of said barrier layer opposing said first side,
• wherein said barrier layer exhibits a valence band energy substantially equal to said valence band energy of said photo absorbing layer and a conduction band energy greater than the conduction band energy of said photo absorbing layer such that said barrier layer forms a conduction energy band offset between the photo absorbing layer and the contact layer,
• wherein said barrier layer thickness and said conduction energy band offsets are sufficient to prevent tunneling of majority carriers between said photo absorbing layer to and said contact area and substantially block the flow of thermalized majority carriers between said photo absorbing layer and said contact area,
• wherein said contact layer comprises individual sections which are separate from each other in a direction across the photo-detector, each section corresponding to an individual detector element,
• wherein said barrier layer extends past the plural individual sections of the contact layer in the direction across the photo-detector, and is monolithically provided for each of the individual detector elements, thereby passivating the photo-detector during operation by blocking the flow of majority carriers to exposed surfaces of said barrier layer.

A photo-detector comprising:

• a photo absorbing layer comprising a p-doped semiconductor exhibiting a conduction band energy and valence band energy;
• a barrier layer exhibiting a thickness, a first side of said barrier layer adjacent a first side of said photo absorbing layer;
• and
• a contact layer comprising a doped semiconductor, said contact layer adjacent a second side of said barrier layer opposing said first side,
• wherein said barrier layer exhibits a conduction band energy substantially equal to said conduction band energy of said photo absorbing layer and a valence band energy less than the valence band energy of said photo absorbing layer such that said barrier layer forms a valence energy band offset between the photo absorbing layer and the contact layer,
• wherein said barrier layer thickness and said valence energy band gap are sufficient to prevent tunneling of majority carriers between said photo absorbing layer and said contact layer and to substantially block the flow of thermalized majority carriers between said photo absorbing layer and said contact layer,
• wherein said contact layer comprises individual sections which are separate from each other in a direction across the photo-detector, each section corresponding to an individual detector element,
• wherein said barrier layer extends past the plural individual sections of the contact layer in the direction across the photo-detector, and is monolithically provided for each of the individual detector elements, thereby passivating the photo-detector during operation by blocking the flow of majority carriers to exposed surfaces of said barrier layer.

A photo-detector comprising:

• a first layer comprising a doped semiconductor exhibiting a valence band energy and a conduction band energy,
• a barrier layer comprising a semiconductor exhibiting a valence band energy and a conduction band energy, a first side of said barrier layer adjacent a first side of said first layer;
• and
• a second layer comprising a doped semiconductor exhibiting a valence band energy and a conduction band energy, said second layer being adjacent a second side of said barrier layer opposing said first side, the second layer having the same majority carrier type as the first layer,
• wherein during operation of the photo-detector the respective valence band energy and conduction band energy of the first layer, the barrier layer, and the second layer allow the flow of photo-generated minority carriers and substantially block the flow of majority carriers between the first layer and the second layer,
• wherein said second layer comprises individual sections which are isolated from each other in a direction across the photo-detector, each section corresponding to an individual detector element,
• wherein said barrier layer extends past the plural individual sections of the second layer in the direction across the photo-detector, and is monolithically provided for each of the individual detector elements, thereby passivating the photo-detector during operation by blocking the flow of majority carriers to exposed surfaces of said barrier layer.

A photo-detector with a reduced dark current, comprising:

• a first layer comprising an electrically conductive semiconductor having majority and minority carrier types with associated energy bands;
• a barrier layer with a barrier energy gap and associated conduction and valence bands, a first side of said barrier layer being adjacent said first layer;
• a second layer comprising an electrically conductive semiconductor having majority and minority carrier types and an associated second layer energy gap, said second layer being adjacent a second side of said barrier layer opposing said first side;
• wherein the relationship between the first and second layer energy bands and the barrier layer conduction and valance band edges enables minority carrier current flow while blocking majority carrier current flow between the first and second layers
• wherein the barrier layer comprises an undoped semiconductor which does not provide electrical conduction laterally within the barrier layer.

A photo-detector—with a reduced dark current, comprising:

• a first layer comprising an electrically conductive semiconductor having majority and minority carrier types with associated energy bands;
• a barrier layer comprising a semiconductor with a barrier energy gap and associated conduction and valence bands, a first side of said barrier layer being adjacent said first layer;
• a second layer comprising an electrically conductive semiconductor having majority and minority carrier types and an associated second layer energy gap, said second layer being adjacent a second side of said barrier layer opposing said first side;
• wherein the relationship between the first and second layer energy bands and the barrier layer conduction and valance band edges enables minority carrier current flow while blocking majority carrier current flow between the first and second layers, and
• further wherein the second layer forms a mesa on the continuous barrier layer such that the first side of said barrier layer laterally extends beyond the mesa, thereby passivating the photo-detector by preventing majority carriers from reaching exposed portions of the barrier layer.