Lateral collection architecture for sls detectors

A photodetector having lateral collection architecture, comprising:

• a planar substrate;
• a first electrically conducting layer deposited on the substrate, the first electrically conducting layer having a single carrier type;
• a second electrically conducting layer deposited on the first electrically conducting layer, the second electrically conducting layer having the same carrier type as the first layer;
• a third electrically conducting layer deposited on the second electrically conducting layer, the third layer having a single carrier type of a type opposite the first layer;
• a fourth electrically conducting layer deposited on the third electrically conducting layer and forming a top surface of the photodetector, the fourth electrically conducting layer having the same carrier type as the third electrically conducting layer;
• a grid of electrically conducting material formed through the top surface, the grid having the same carrier type as the first electrically conducting layer and penetrating to the second electrically conducting layer to define a plurality of pixels, each pixel formed from the third and fourth electrically conducting layers and isolated from all other pixels by the grid and by the second electrically conducting layer;
• a plurality of first Ohmic contacts, each first Ohmic contact electrically coupled to one of the pixels at the top surface of the planar photodiode;
• and
• a common Ohmic contact electrically coupled to the planar substrate.

A method for fabricating a photodetector array having lateral collection architecture, comprising:

• providing a substrate suitable for depositing thereon one or more photosensitive layer structures;
• depositing on the substrate a first electrically conducting layer having a single carrier type;
• depositing on the first electrically conducting layer a second electrically conducting layer of a photosensitive quantum confined detector material having the same carrier type as the first layer;
• masking the second layer to locate unmasked regions for conversion;
• converting the unmasked regions to doped regions having a carrier type opposite that of the first and second layers;
• masking the doped regions to define locations for deposition of first Ohmic contacts on each of the doped regions;
• depositing the first Ohmic contacts on the locations defined in the previous step;
• and
• providing electrical connections to the first Ohmic contacts, and to the first layer via a second Ohmic contact.

A method for fabricating a photodetector or photodetector array, comprising:

• providing a substrate suitable for depositing thereon one or more photosensitive layer structures;
• depositing on the substrate a first electrically conducting layer having a single carrier type;
• depositing a second electrically conducting layer of a photosensitive quantum confined detector material, the layer having the same carrier type as the first layer;
• depositing a third electrically conducting layer of a photosensitive quantum confined detector material, the layer having a single carrier type of a type opposite the first layer;
• depositing a fourth electrically conducting layer having a wider bandgap than the third electrically conducting layer and having a same carrier type as the third layer;
• masking the fourth layer to locate pixels between unmasked regions;
• converting unmasked regions to doped regions, each doped region having the carrier type of the first and second layers to a depth penetrating to the second layer;
• masking the fourth layer to define locations for deposition of first Ohmic contacts on each of the pixels;
• depositing the first Ohmic contacts on surfaces of the pixels;
• and
• providing electrical connections to the first Ohmic contacts, and to the first layer via a second Ohmic contact.

A cap-doped photodiode array, comprising:

• a planar substrate;
• a plurality of mesas of electrically conducting material arranged on top of the substrate, each mesa having a top surface and a sidewall, the electrically conducting material having a single carrier type, each mesa having a wide bandgap quaternary passivation layer of a carrier type opposite that of the electrically conducting layer along its top surface and along at least a part of its sidewall;
• a plurality of Ohmic contacts, each Ohmic contact electrically coupled to a top surface of a mesa;
• and
• electrical connections coupled to the Ohmic contacts and to the planar substrate.

A method for fabricating a cap-doped photodetector pixel array having a wide bandgap passivation layer, comprising:

• providing a substrate suitable for depositing a photosensitive layer structure thereon;
• forming on the substrate an electrically conducting layer of a photosensitive quantum confined detector material having a single carrier type;
• delineating a plurality of mesas from the electrically conducting layer;
• converting a layer on top of each mesa and along at least a part of sidewalls of each mesa to a quaternary material having a carrier type opposite that of the electrically conducting layer;
• masking top surfaces of the mesas to define unmasked locations for deposition of Ohmic contacts;
• depositing Ohmic material on the unmasked locations;
• and
• providing electrical connections to the Ohmic contacts and to the substrate.