What component serves as the semiconductor layer in a semiconductor detector?

In a semiconductor detector, the semiconductor layer is a critical component due to its role in detecting radiation by generating charge carriers (electrons and holes) when it interacts with high-energy particles or photons. The electron-emissive crystal serves as the semiconductor material, which is typically made from elements like silicon or germanium.

When radiation passes through this semiconductor material, it produces electron-hole pairs; these pairs are then separated by an applied electric field, allowing them to contribute to an electrical signal that can be measured. This makes the electron-emissive crystal essential for the operation of semiconductor detectors, as it is responsible for the initial interaction with radiation and the conversion of that interaction into an electrical signal, ultimately facilitating radiation measurement.

In contrast, the other options do not serve as the semiconductor layer: a conductive plate is typically used for establishing electrical connections rather than acting as the semiconductor itself, an amplifier is used to boost electrical signals, and a photoconductor, while also a type of semiconductor, functions differently—primarily in response to light rather than direct ionizing radiation.