Intersubband absorption in GaN nanowire heterostructures at mid-infrared wavelengths. (11th July 2018)

• Record Type: Journal Article
• Authors: Ajay, A; Blasco, R; Polaczyński, J; Spies, M; Den Hertog, M I; Monroy, E
• Is Part Of: Nanotechnology. Volume 29:Number 38(2018)
• Publication Date: 2018-07-11
• Subjects: GaN -- nanowire -- infrared -- intersubband; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/aacf55
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: In this paper, we study intersubband characteristics of GaN/AlN and GaN/Al0.4 Ga0.6 N heterostructures in GaN nanowires structurally designed to absorb in the mid-infrared wavelength region. Increasing the GaN well width from 1.5 to 5.7 nm leads to a red shift of the intersubband absorption from 1.4 to 3.4 μ m. The red shift in larger quantum wells is amplified by the fact that one of the GaN/AlN heterointerfaces (corresponding to the growth of GaN on AlN) is not sharp but rather a graded alloy extending around 1.5–2 nm. Using AlGaN instead of AlN for the same barrier dimensions, we observe the effects of reduced polarization, which blue shifts the band-to-band transitions and red shifts the intersubband transitions. In heavily doped GaN/AlGaN nanowires, a broad absorption band is observed in the 4.5–6.4 μ m spectral region.