We proposed a novel CdTe X-ray image sensor, which was driven by the FEA, to obtain high spatial resolution X-ray images and have demonstrated the principle operation by using the CdTe image sensor with one pixel. We have also fabricated a FEA matrix with 12×12 pixels to obtain X-ray images. For the further improvement of spatial resolution in the CdTe image sensor, we have proposed a novel double-gated FEA with a focusing lens, which was fabricated by using the etch-back method. The double-gated FEA showed a good focusing characteristic without significant decrease of the emission current, when the height of the focus electrode was optimized. The CdTe image sensor driven by the double-gated FEA is promising for an ultra-high-resolution X-ray image sensor.
