Optoelectrical properties of a heterojunction consisting ofp‐type hydrogenated amorphous silicon (a‐Si:H) onn‐type crystalline silicon (c‐Si) have been investigated by measuring current–voltage and capacitance–voltage characteristics and the temperature dependence of the dark current. It was found that the hole injection fromn‐typec‐Si intop‐typea‐Si:H depended mainly on control of the impurity concentration ina‐Si:H doped with boron at the junction interface. The results obtained for the dark current and photocurrent (with 100 1×illumination) were 7.3 nA cm−2and 41 &mgr;A cm−2, respectively, at an applied voltage of 5 V. These results hold promise for applications to a silicon vidicon target without a diode array.