Ultra-long germanium oxide nanowires: Structures and optical properties

This paper reports the successful synthesis, structural and optical characterizations of ultra-long germanium oxide (GeO2) nanowires. The ultra-long GeO2 nanowires were synthesized by facile and simple thermal evaporation process using high-purity Ge powder on Au/Si substrate at 1200 °C. The prepared nanowires were investigated by various techniques in terms of their morphological, structural, compositional and optical properties. By detailed morphological, structural and compositional studies, it is confirmed that the prepared GeO2 nanowires are pure, grown in very high density, and possessing well-crystallinity. A VLS growth mechanism is proposed for the formation of as-prepared GeO2 nanowires. The optical properties of the as-prepared nanowires were conducted by room-temperature photoluminescence (PL), revealing that the nanowires exhibited a prominent UV emission peak centered at 411 nm and a weak green emission peak at 526 nm, and hence demonstrating good optical properties with fewer deep-level defects.