SYNCHROTRON X-RAY PHOTOCONDUCTOR DETECTOR ARRAYS MADE ON MBE GROWN CDTE

We have been fabricating x-ray photoconductor linear array detectors u sing molecular beam epitaxially (MBE) grown (111)B undoped CdTe layers on (100) Si substrates. A novel technique was developed to remove the Si and to mount the fragile MBE grown CdTe layers onto insulating cer amic substrates. 256 channel linear photoconductor array devices were fabricated on the resulting CdTe layers. The resistivity of MBE (111)B CdTe was high (>10(8) Omega cm) enough to utilize the material for lo w energy (8 similar to 25 keV) x-ray detectors. The stability of the d etectors are satisfactory, and they were tested at room temperature ro utinely for over a year. The performance of the photoconductor was gre atly improved when the detector was cooled to 230K. Due to its reduced dark current at low temperatures, the dynamic range of the detector r esponse increased to nearly four decades at 230K.