Multilayer Structure Gaas Photoemission Surface Photovoltage Spectrum Characteristics Analysis

Photoelectric detection materials and devices widely used in the military, astronomical observation, security and other industries. The fast response, high gain, low noise GaAs photoemission material photodetectors widely used in photoelectric detection.Photocathode and other semiconductor devices have complex semiconductor multilayer structure. This paper used the nondestructive, convenient surface photovoltage (SPV) spectroscopy to determine the characterization of multilayer structure semiconductor.First, the concept of surface photovoltage was explained. Different SPV signal detection methods were compared. Kelvin probe and metal-insulator-semiconductor (MIS) configuration for surface photovoltage measurement was compared in detail. The MIS configuration with air gap insulator was adopted for SPV measurements. The surface photovoltage spectroscopy test system for multi-layer GaAs structure was introduced. Then, mechanisms of SPV for AlGaAs/GaAs and GaAs/AlGaAs/GaAs structures were theoretically analyzed. Band diagrams for p-Al0.63Gao.37As/p-GaAs and p-GaAs/P-AI0.57Ga0.43AS/si-GaAs structure ware given out. One-dimensional continuity equation was adopted for determine the distribution of excess minority carrier. Solve one-dimensional continuity equation with surface and interface boundary condition, construct the Surface photovoltage spectroscopy model. The characteristics of p-GaAs/p-Al0,57Ga0.43As/si-GaAs structure were discussed step by step. Last, SPV model of the multi-layer structure GaAs was verified experimentally. Dependence of the surface photovoltage on incident photon intensity for band-to-band excitation was adopted for the calculation of ideality factor. SPV of AlGaAs/GaAs and GaAs/AlGaAs/GaAs structure have been measured. All of characteristics been calculated. A comparative research on GaAs photocathodes before and after activations has been done. The multi-layer GaAs structure photovoltage theoretical model was verified. The practicality of surface photovoltage spectroscopy was proved.