  The quality of Cadmium Zinc Telluride (CZT) detectors is steadily improving.
For state of the art detectors, readout noise is thus becoming an increasingly
important factor for the overall energy resolution. In this contribution, we
present measurements and calculations of the dark currents and capacitances of
0.5 cm-thick CZT detectors contacted with a monolithic cathode and 8x8 anode
pixels on a surface of 2 cm x 2 cm. Using the NCI ASIC from Brookhaven National
Laboratory as an example, we estimate the readout noise caused by the dark
currents and capacitances. Furthermore, we discuss possible additional readout
noise caused by pixel-pixel and pixel-cathode noise coupling.
