{'fraction_non_alphanumeric': 0.04234122042341221, 'fraction_numerical': 0.06102117061021171, 'mean_word_length': 4.955555555555556, '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}}
Photoluminescence Studies on Very High-Density Two-Dimensonal Electron Gases in Pseudomorphic Modulation-Doped Quantum Wells

We present photoluminescence studies on highly dense two-dimensional electron gases in selectively Si δ-doped GaAs/In0.18Ga0.82As/Al0.25Ga0.75As quantum wells (Ns = 4.24 × 1012 cm-2). Five well-resolved photoluminescence lines centered at 1.4194, 1.4506, 1.4609, 1.4695 and 1.4808 eV were observed, which are attributed to the subband exciton emission. The subband separations clearly exhibit the feature of a typical quantum well with triangle and square potential. These very intensive and sharp luminescence peaks with linewidths of 2.2 to 3.5 meV indicate the high quality of the structures. Their dependence on the excitation intensity and temperatures are also discussed.