InGaAs/InP photocathode grown by solid-source MBE

As an III-V semiconductor material, InxGa(1-x)As can response from 0.87 mu m (GaAs) to 3.5 mu m (InAs) by tuning the relative amount of Gallium in the alloy. In order to get better the response of the photocathode in near infrared radiation region (1 similar to 1.7 mu m), InGaAs/InP heterostructure is widely used for photocathode material. The only composition of In0.53Ga0.47As is lattice matched to the InP substrate and their spectral response is from 0.9 mu m to 1.6 mu m. thus In0.53Ga0.47As/InP heterostructure is selected for near infrared response photocathode. The In0.53Ga0.47As layer has been grown on InP substrate used for photocathode by solid source molecular beam epitaxiy (SS-MBE). The photocathode samples were grown to optimize the growth temperature, III/V ratio and growth rate. The In0.53Ga0.47As layer crystalline quality and component were performed by applying high resolution X-ray diffractometer, surface roughness investigations were performed by applying atomic force microscopy. The Be doping characteristic was checked by the electrochemical capacitance-voltage(ECV). The optical performance of the photocathode is measured by the spectral meter. The collected information is being used to correct and enhance growth characteristics and optimize InGaAs/InP photocathode structure to increase spectral response and quantum efficiency.