Research On Spectral Response Testing System For QWIP

Quantum Well Infrared Photodetector (QWIP) is a new type of infrared devices that combines mutually modern film growth techniques and microelectronics. It has been extensivly applied in defense, industry, medicine, and so on. The spectral response is an important basis for infrared detector in the infrared test, which decides the application range and sensitivity of photodetector. This paper invented a new device of measuring infrared detector spectral responsivity, which is sponsored by research projects of national priority.With the help of computer hardware and LabVIEW, the performance parameters of QWIP could be measured successfully. Main jobs are summarized below:First, test method of integral response and spectral response of infrared detector was researched of the basis of analysis the principle and performance parameters of QWIP. Combining blackbody radiation measurement principle and FTIR, the way to test QWIP's key performance parameters is proposed, which can be achieved on the overall test.Second, the total solution of system was established. The hardware design and system test were completed. Then the test software was designed. The digital oscilloscope and computer work synchronously by ethernet. The communication between FTIR and computer is achieved by utilizing RS232 serial. The characteristic data was automatically acquired by controlling the apparatus based on LabVIEW8.0.Third, the dark current, voltampere characteristic and integral response of two types of QWIP were measured and analyzed under variant bias voltage with cryostat in room. And the relationship between resistance and work temperature of detector were investigated. The spectrum of light was, obtained and the feasibility of the entire test system was proved by measuring spectral response of pyroelectric detector with improved spectral response measurement system. Afterwards, the paper studied spectral response curve on the basis of spectral response of QWIP. Measurement results show that the spectral range is 2.5-18μm, the peak wavelength of tested detector is 8.5μm and peak responsivity is 0.046A/W.Last, all work in this paper have been summarized, and the method is put forward.