Recent results from the development of a far-infrared n-type GaAs detector array for FIRST

Use of ta photoconductor array in the wavelength range from about 100 to 300 microns could add to the capability of the far-infrared imaging spectrometer in the model payload of FIRST (ESA's far-infrared and submillimeter space telescope). The GaAs detector array is a completely new development and will be included in an ESA-sponsored detector development program. The material offers the advantage of extending the wavelength range of photoconductors considerably. Essential improvement of material quality is required to bring dark current and NEP at operating temperatures around 1 K down to levels of state-of-the-art photoconductors. Recent progress has led to the production of extremely high purity GaAs layers using liquid phase epitaxy. Layers with a thickness of a few hundred microns were produced only a short time ago. They are considered good candidates to start investigations and preparation of detectors. This paper discusses recent results of the GaAs material research, detector design, and progress of array development.