{'fraction_non_alphanumeric': 0.03121516164994426, 'fraction_numerical': 0.013377926421404682, 'mean_word_length': 5.323943661971831, '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}}
Efficient surface passivation using two-step ammonium sulfide based treatment for GaN/AlGaN heterojunction phototransistors

The effects of different ammonium sulfide [(NH4)2Sx]-based treatments on the surface passivation of dry-etched and thermally recovered GaN epilayer have been investigated. A two-step treatment using HCl followed by the mixture of (NH4)2Sx and isopropyl alcohol demonstrated a more effective removal of intrinsic oxide layer and formation of sulfide passivation. The compensating centers on both the p- and n+-type GaN surfaces were significantly reduced. The fabricated base-floating GaN/Al0.1GaN heterojunction phototransistors (HPTs) with the surface passivation showed improved I–V and enhanced optical gain due to the effective suppression of surface recombination current. A maximum gain of 1.3 × 105 was obtained at 5 V bias in the HPTs using the two-step treatment.