Enhanced light emission from germanium microdisks on silicon by surface passivation through thermal oxidation. (30th March 2016)

• Record Type: Journal Article
• Authors: Xu, Xuejun; Hashimoto, Hideaki; Sawano, Kentarou; Nohira, Hiroshi; Maruizumi, Takuya
• Is Part Of: Applied physics express. Volume 9:Number 5(2016:May)
• Publication Date: 2016-03-30
• Subjects: Physics -- Periodicals; Technology -- Periodicals; 621.05
• DOI: 10.7567/APEX.9.052101
• Languages: English
• ISSNs: 1882-0778

Abstract

Abstract: We have observed enhanced direct-gap light emission from undoped and n-doped germanium microdisks on silicon. The enhancement is attributed mainly to increased carrier density due to surface passivation of the dry-etched sidewall. The enhancement factor increases as the disk size decreases, approaching 4 for microdisks with radii of 1 µm. To achieve maximum enhancement and not modify the geometric structure of resonators, 450–500 °C is found to be the best temperature window. Thermal oxidation is also effective for the degraded interface induced by sputtered Al2 O3 . These results indicate that thermal oxidation is a promising method suitable for fabrication of low-threshold germanium lasers.