γ-Fe2O3 nanocrystals were deposited on the silicon nano-porous pillar array(Si-NPA) template which has special micro-nano hierarchical structure to prepare a γ-Fe2O3/Si-NPA humidity sensor.The size of γ-Fe2O3 nanocrystal could be controlled by a new chemical method of microemulsion and hydrothermal.Room temperature capacitive and resistive sensitivity of this γ-Fe2O3/Si-NPA sensor was investigated.The sensor's capacitance and resistance are very sensitive to humidity.When the relative humidity(RH) changed f...