Suppression of the quantum-confined Stark effect in polar nitride heterostructures

Abstract

Recently, we suggested an unconventional approach (the so-called Internal-Field-Guarded-Active-Region Design "IFGARD") for the elimination of the quantum-confined Stark effect in polar semiconductor heterostructures. The IFGARD-based suppression of the Stark redshift on the order of electronvolt and spatial charge carrier separation is independent of the specific polar semiconductor material or the related growth procedures. In this work, we demonstrate by means of micro-photoluminescence techniques the successful tuning as well as the elimination of the quantum-confined Stark effect in strongly polar [000-1] wurtzite GaN/AlN nanodiscs as evidenced by a reduction of the exciton lifetimes by up to four orders of magnitude. Furthermore, the tapered geometry of the utilized nanowires (which embed the investigated IFGARD nanodiscs) facilitates the experimental differentiation between quantum confinement and Stark emission energy shifts. Due to the IFGARD, both effects become independently adaptable.

Lateral‐Polarity Structure of AlGaN Quantum Wells: A Promising Approach to Enhancing the Ultraviolet Luminescence

“…With increasing QW thickness from 2 to 4 nm, wavefunction overlap decreases from 51.4% to 24.9% for N‐polarity, suggesting less effective quantum confinement as QW thickness increases. This is in good accordance with reports from Schlichting et al However, wavefunction overlap increases slightly from 71.4% to 83.7% with thicker QW thickness in the case of p = 0 since the wavefunctions of both electrons and holes are located in the center of the QW due to the absence of the internal electric field. Considering that radiative recombination would occur in both N‐polar domains and IDBs, a balance value of 3 nm QW thickness was chosen in this work as annotated by the dashed circle (Figure c).…”

Coherent-interface-induced strain in large lattice-mismatched materials: A new approach for modeling Raman shift

“…( 7) with R GaN = 6.5 ± 0.3 and R AlN = 7.7 ± 0.4 can be used to correctly estimate the biaxial strain in IIInitrides via Raman spectroscopy. The considerable application potential of the present findings could benefit a broad readership interested in III-nitride-based optoelectronics and power electronics devices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][85][86][87][88]].…”

“…Specifically, III-nitride based heterostructures provide new opportunities for a wide range of research and device applications, such as piezotronics and piezophototronics [1], self-powered photoelectrochemical-type photodetectors [2], room-temperature quantum emitters [3], single photon emitters [4][5][6], resonant tunneling diodes [7], highelectron-mobility transistors [8,9], efficient photoelectrocatalysts for solar water splitting [10], multi-wavelength light-emitting diodes (LEDs) [11,12], and deep ultraviolet (DUV)-LEDs [13][14][15][16][17]. AlGaN-based DUV-LEDs represent a sustainable alternative to replace the environmentally harmful conventional mercury lamps [18] and thus, are becoming crucial for many applications such as water purification and/or inactivation of microorganisms, including bacteria, fungi, and viruses [19,20].…”

Evidence of Carrier Localization in AlGaN/GaN‐Based UV Multiple Quantum Wells with Opposite Polarity Domains Provided by Nanoscale Imaging

“…Control of the emission wavelength is challenging, because it is related to various factors, including alloy compositions, QW confinement, and strain conditions of the active regions. [30,31] Introduction of different polarity domains into the system makes it even more complex. Thus, it is crucial to distinguish the contribution of each factor.…”