Optical polarization characteristics ofm-oriented InGaN/GaN light-emitting diodes with various indium compositions in single-quantum-well structure

Abstract

Spontaneously polarized light emission from m-plane InGaN/GaN light-emitting diodes was studied as a function of In composition in the InGaN single quantum-well layer. Emission wavelength was varied between 394 and 472 nm. A strong correlation was confirmed between optical polarization and In composition; the higher the In composition, the stronger the optical polarization. The photon-energy difference between the emission spectra associated with the two polarizations, ΔM, was evaluated as a function of current. ΔM exhibited a negative monotonic current dependence for the 394 nm emitting sample and the dependence was changed to positive monotonic as the wavelength became longer towards 472 nm. This change was tentatively attributed to the valence band mixing and the crystal momentum conservation that became relevant with the band filling. ΔM and optical polarization exhibited only a moderate correlation; the Fermi–Dirac function has been used to explain the weakened optical polarization under increased current injection.

Stimulated emission in GaN-based laser diodes far below the threshold region

“…Third, the dependences of polarization ratio on current are different. The polarization ratio of PA is almost unity with current while that of m-plane spontaneous emission slight decreases as reported by Krame [30] and DenBaars [31]. Therefore, the PA is distinct from the spontaneous emission observed in m-plane in phenomenology.…”

Linearly Polarized Light Emission from InGaN/GaN Quantum Well Structure with High Indium Composition

“…16 17 Evolution of stacking faults and dislocations in the sample was observed from the dark field TEM image of Figure 1(b). Using g · b extinction rules, when viewed along c-direction with g = −2110, partial dislocations (b = 1/5 20-23 ), threading dislocations (b a+c = 1/3 [11][12][13][14][15][16][17][18][19][20][21][22][23]), and prismatic stacking faults (R = 1/2 [10][11]) could be observed. It was clear that misfit dislocations and stacking faults are generated at the interface between InGaN and GaN layers.…”

Impurity-related binding energy in strained (In,Ga)N asymmetric coupled QWs under strong built-in electric field

“…For instance, Mutta et al [4] have reported the experimentally investigations using transmission electron microscopy and photoluminescence on WZ (In,Ga)N/GaN QW for various structure parameters. The effects Inconcentration on the optical properties of WZ (In,Ga)N/GaN QW [5] and on the optical polarization characteristics of m-oriented InGaN/ GaN QW LED [6,7] are investigated. On the other hand, some theoretical studies are reported.…”