{'fraction_non_alphanumeric': 0.017159199237368923, 'fraction_numerical': 0.0, 'mean_word_length': 5.402439024390244, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Photodetectors For High Speed Image Scanners On GaAs

Recent research into overlapping metal-gate charge-coupled devices on gallium arsenide has shown that meander channel image scanners can be produced using the more conventional scanner architecture familiar to silicon-based CCD imagers. In these conventional structures the photodetectors have front surface sensitivity and are placed along-side the CCD channel. There exist certain important applications where this type of architecture is preferred: among them are a) linear edge scanners for optical waveguide arrays, and b) large two-dimensional image scanners where wafer thinning is impractical for backside illumination. Using anodically isolated overlapping metal-gate CCD structures both linear and meander-channel two-phase devices have been produced on GaAs. The meander structure offers the optimum ratio of detector area to total device area. Its availability now on GaAs offers high speed scanning rates that exceed those of silicon based devices by at least an order of magnitude.