Amorphous　silicon/crystalline　silicon　heterojunction　solar　cells　have　high　open-circuit　voltages　(Voc)　due　to　excellent　passivation　on　n-type　wafer　surfaces　by　thin　intrinsic　amorphous　silicon　layers.　In　this　paper,　we　focus　on　development　of　high　efficiency　rear-emitter　heterojunction　solar　cells　using　n-type　silicon　wafers,　mainly　in　three　aspects:　1)　intrinsic　amorphous　silicon　layer　optimization　for　obtaining　superior　wafer　surface　passivation,　2)　n-type　amorphous　silicon　film　optimization,　as　a　window　layer,　for　high　Voc　and　fill　factor　(FF),　and　3)　transparent　conductive　oxide　(TCO)　layer　development　for　high　transmittance　and　well　balancing　between　short-circuit　current　density　(Jsc)　and　FF.　After　process　optimization,　we　attained　21.7%　certified　efficiency　on　a　152.3cm(2)　n-type　silicon　wafer　with　Jsc　of　38.25mA/cm(2)　and　Voc　of　721mV.