Abstract: In one aspect, a method includes forming a pit in a top surface of a substrate by removing a portion of the substrate and growing a semiconductor material with a bottom surface on the pit, the semiconductor material different than the material of the substrate. The pit has a base recessed in the top surface of the substrate. In another aspect, a structure includes a substrate having a top surface, the substrate including at least one pit having a base lower than the top surface of the substrate, and a semiconductor material having a bottom surface formed on the base of the pit.

Abstract: In a general aspect, a device includes a substrate, a light transmission formed on a top surface of the substrate, a first contact, and a second contact. The light transmission structure includes a first doped region; a second doped region doped oppositely to the first region; a lateral junction between a part of the first doped region and a part of the second doped region, the lateral junction oriented substantially perpendicular to the top surface of the substrate; and a vertical junction between a part of the first doped region and a part of the second doped region, the vertical junction oriented substantially parallel to the top surface of the substrate. The first contact is in electrical contact with the first region and the second contact is in electrical contact with the second region.

Abstract: In a general aspect, a device includes a substrate, a light transmission formed on a top surface of the substrate, a first contact, and a second contact. The light transmission structure includes a first doped region; a second doped region doped oppositely to the first region; a lateral junction between a part of the first doped region and a part of the second doped region, the lateral junction oriented substantially perpendicular to the top surface of the substrate; and a vertical junction between a part of the first doped region and a part of the second doped region, the vertical junction oriented substantially parallel to the top surface of the substrate. The first contact is in electrical contact with the first region and the second contact is in electrical contact with the second region.