Photoluminescence in Nitrogen-Rich a-SiNx:H

ABSTRACTWe report the measurement of photoluminescence (PL) from nitrogen-rich hydrogenated amorphous silicon nitride (a-SiN1.6:H) films. Excitation at 4.8 eV gives a PL spectrum of approximately Gaussian lineshape centered at 2.9 eV with a full width at half maximum of 1.4 eV. The PL intensity at 2.9 eV fatigues under continuous 4.8 eV excitation, but may be restored by thermal annealing or photobleaching with light of energy ≥ 2 eV. For emission at 2.9 eV, the PL excitation spectrum in the range 3.0 to 5.2 eV follows the a-SiN1.6:H film optical absorption edge at low energy and then decreases with a maximum at approximately 5.4 eV. The PL results are discussed within the framework of a negative effective electron-electron correlation energy (negative Ueff) for the dominant defect (silicon atom bonded to three nitrogen atoms).