In this paper, some new types ofp‐Si(100) photocathodes withn‐K3Sb,n‐Na3Sb, andp‐Cs3Sb intermediate layers are fabricated. They are the (Si‐K3Sb‐Cs)‐O‐Cs and (Si‐Na3Sb‐Cs)‐O‐Cs negative electron affinity heterojunction photocathodes, and the (Si‐Cs3Sb‐Cs)‐O‐Cs positive electron affinity photocathode. For cathodes withn‐K3Sb,n‐Na3Sb, andp‐Cs3Sb intermediate layers, the maximum photoemission sensitivities attainable are, respectively, 1050, 950, and 150 &mgr;A/lm, and the measured minimum work functions of these cathodes are, respectively, 0.9, 1.0, and 0.85 eV. The photoemission stability of the Si photocathode with an alkali antimonide intermediate layer is better than that of the conventional Si‐O‐Cs and GaAs‐O‐Cs cathodes. The stability of the cathode is also related to the states of the cesium and oxygen during the activation process and the light illumination condition.