Semiconductor photocathode and semiconductor photocathode apparatus using the same

摘要

Formed on a semiconductor substrate (10) is a first semiconductor layer (20; light absorbing layer) of p-type which has a first dopant concentration and generates an electron in response to light incident. Formed on the first semiconductor layer (20) is a second semiconductor layer (30; electron transfer layer) of p-type having a second dopant concentration lower than the first dopant concentration. A contact layer (50) forms a pn junction with the p-type second semiconductor layer (30). A surface electrode (80) is formed on and in ohmic contact with the contact layer (50). A third semiconductor layer (40; activation layer) is formed within an opening of the contact layer (50) on the surface of the second semiconductor layer (30). Embedded in the second semiconductor layer (30) is a semiconductor section (60; channel grid) having a third dopant concentration. Thus, the quantum efficiency is improved, while structural pixel separation becomes unnecessary at an open area ratio of 100%, and signal modulation is enabled.