Implantable therapeutic devices and methods for endovascular placement of devices at a target site, such an opening at a neck of an aneurysm, are disclosed. Each pixel in the image sensor includes a plurality of superposed photosensitive p-n junctions with individual charge integration regions. Hence, the users of the two image display apparatuses may communicate through images with one another, prompted by interesting information such as a similarity in hobbies or preferences or the like. The transistor has exposed surface portions of the Schottky layer beween the source electrode and the drain electrode adjacent to the gate electrode contact region of the Schottky layer. An alignment key may be formed by selectively etching the oxide layer.