Magnetic resonance studies of InGaN-based quantum well diodes

Abstract

Photoluminescence (PL) based optically detected magnetic resonance (ODMR) studies as well as electroluminescence detected and electrically detected magnetic resonance (ELDMR and EDMR, respectively) measurements of InxGa1−xN quantum wells were performed. In the ODMR, two PL-enhancing resonances were observed: an electron resonance and a hole resonance. The electron resonance is consistent with expectations for the g value in bulk InxGa1−xN for x ≈ 0.4 but deviates significantly in an x≈0.3 sample. Possible reasons for this include the effects of strain and confinement. The hole resonance is qualitatively similar to observations in Mg-doped GaN, but more isotropic in the x ≈ 0.3 diode than in the x ≈ 0.4 sample. We measure relatively long radiative lifetimes (as long as ∼0.2 ms) in the ODMR which facilitate the observation of the resonances and indicate that the electron and hole are spatially separated either by potential fluctuations within the quantum well or by the trapping of the hole at an acceptor in the player of AlGaN whch serves as one of the confining barriers. In the EDMR and ELDMR experiments, the signal is primarily due to a reduction in the nonradiative recombination at resonance. While the ODMR is alwyas emission-enhancing, the ELDMR is luminescence-quenching, supporting the notion that techniques are probing different centers.