Effect of doping on the intersubband absorption in Si- and Ge-doped GaN/AlN heterostructures

Abstract

In this paper, we study band-to-band and intersubband characteristics of GaN/AlN heterostructures (planar and nanowires) structurally designed to absorb in the short-wavelength infrared region, particularly at 1.55 microns. We compare the effect of doping the GaN sections with Si and Ge, and we discuss the variation of free-carrier screening with the doping density and well/nanodisk size. We observe that nanowire heterostructures consistently present longer photoluminescence decay times than their planar counterparts, which supports the existence of an in-plane piezoelectric field associated to the shear component of the strain tensor, leading to lateral electron-hole separation. We report intersubband absorption covering 1.45 microns to 1.75 microns using Ge-doped quantum wells, with comparable performance to well-studied Si-doped planar heterostructures. We also report comparable intersubband absorption in Si- and Ge-doped nanowire heterostructures indicating that the choice of dopant is not an intrinsic barrier for observing intersubband phenomena. In addition, we calculate the spectral shift of the intersubband absorption due to many body effects as a function of the doping concentration.

References in corpus (5)

• Single nanowire solar cells beyond the Shockley-Queisser limit
• Ge doping of GaN beyond the Mott transition
• Carrier Confinement in GaN/AlGaN Nanowire Heterostructures for 0 < x <= 1
• Screening of the quantum-confined Stark effect in AlN/GaN nanowire superlattices by Germanium doping
• Long-lived excitons in GaN/AlN nanowire heterostructures

Cited by in corpus (9)

• Near-infrared intersubband photodetection in GaN/AlN nanowires
• Nanowire photodetectors based on wurtzite semiconductor heterostructures
• Electrical and Optical Properties of Heavily Ge-Doped AlGaN
• Effect of the nanowire diameter on the linearity of the response of GaN-based heterostructured nanowire photodetectors
• Assessment of AlGaN/AlN superlattices on GaN nanowires as active region of electron-pumped ultraviolet sources
• Ultraviolet Photodetectors based on GaN and AlGaN/AlN Nanowire Ensembles: Effects of Planarization with Hydrogen Silsesquioxane and Nanowire Architecture
• Solubility limit of Ge Dopants in AlGaN: a Chemical and Microstructural Investigation down to the Nanoscale
• Effect of Ge-doping on the short-wave, mid- and far-infrared intersubband transitions in GaN/AlGaN heterostructures
• Near- and mid-infrared intersubband absorption in top-down GaN/AlN nano- and micropillars