Optical gain in InGaN∕GaN quantum well structures with embedded AlGaN δ layer

Abstract

Optical gain characteristics of InGaN∕GaN double quantum well (QW) structures with embedded AlGaN δ layer are investigated using the multiband effective mass theory. These results are compared with those of single QW structure without a δ layer. The theoretical energies show very good agreement with the experimental results for both single and double QW structures. The inclusion effect of a δ layer is found to be dominant at a relatively low carrier density. A double QW structure has larger optical gain than the single QW structure, in particular, at higher carrier density.

Performance Improvement of Nitride-Based Light-Emitting Diode With a Thin Mg-Delta-Doped Hole Injection Layer

“…Extensive works had been reported on achieving high internal quantum efficiency (IQE) in LEDs by using QW designs that can address the charge separation issues. The related representative QW designs include semi/non-polar InGaN QWs [1], [2] and polar QWs structures with large electron-hole wavefunction overlap such as (1) Staggered QW [3]- [8], (2) Type-II QW [9]- [11], (3) InGaN-delta-AlGaN QW [12], [13], (4) InGaN-delta-InN QW [14], and (5) Strain-compensated QW [15], [16]. On the other hand, the efficiency droop effect caused by carrier leakage (thermionic carrier leakage and polarization-induced leakage) [17]- [20] and/or Auger processes [21]- [23], which strongly limits the QE and hampers the further development of nitride-based LEDs, has been widely reported.…”

Staggered InGaN quantum well diode lasers emitting at 500 nm

“…However, both cases will reduce the electron-hole wave function overlap (Γ e_hh ) significantly in the InGaN QW, which prevents the high performance conventional InGaN QW LEDs emitting in the green regime as well as the extension of the InGaN based LD to green lasing wavelength. Several other approaches have been proposed to enhance the electron-hole wave function overlap (Γ e_hh ) such as 1) embedded AlGaN δ layer in InGaN QW [5][6], 2) staggered InGaN QW [7][8], 3) type-II InGaN-GaNAs QW [9][10] and 4) strain-compensated InGaN-AlGaN QW [11][12].…”

Growth of staggered InGaN quantum well light-emitting diodes emitting at 520-525 nm employing graded temperature profile

“…Both approaches lead to severe reduction in the electron-hole wavefunction overlap (Γ e_hh ). Recently, several recent approaches have been proposed to enhance the electron-hole wave function overlap (Γ e_hh ) such as non-polar InGaN QW [5][6], embedded AlGaN δ layer in InGaN QW [7][8], staggered InGaN QW [9][10], type-II InGaN-GaNAs QW [11][12], and strain-compensated InGaN-AlGaN QW [13][14].…”