The Surface Treatment And Passivation Studying Of CZT Crystal

CdZnTe(CZT) nuclear detectors have been widely utilized as x,γray detectors and image instruments for its high detection efficiency and good energy resolution. Since the performance of detectors is greatly influenced by the surface treatment and the passivation of the crystal, the main purpose of this thesis is to study the surface treatment and passivation processes of CZT nuclear radiation detector.CZT crystal with its brittleness is easy to produce crack or crash under the external force. So, during incising the CZT crystal, we should control the speed of incision and temperature of cooling water to avoid the"crack layer". We choose the speed of incision to be 1 millimeter per minute and the thickness of wafer is about 2.5 millimeter after repeated experiments..In the course of the grind of the CZT wafer, the rate of grind is vitally important while the pressure is determinate. Low rate of grind leads to low efficiency, while high rate might make CZT wafer crack, even crash, resulting in the unsteadiness of the instrument which causes the roughness of the surface. Through repeated testing and studying, we draw a conclusion that the optimum rate of the grind of the CZT wafer is 40 revs per minute.After the mechanical polishing, the surface of the CZT wafers appears very luminant and smooth by the naked eye, but a lot of nicks and spots can be observed on the surface of the CZT wafers by the optical microscope. Br-methanol (BM) and Br-lactic acid-glycol(LB) solutions which could decrease the surface roughness effectively were employed to polish the CZT surface,and a possible polishing...