Photoluminescence Mechanism in Heavily Si-Doped GaAsN

The photoluminescence (PL) mechanism is discussed for heavily Si-doped GaAsN, and the evaluation method of electron effective mass (m(e)*) is proposed using its PL peak energy. PL peak energy monotonically decreases as increasing temperature, so the S-shape characteristic is vanished for this heavily Si-doped GaAsN as opposed to moderately Si-doped GaAsN. This result shows that the dominant PL process is an optical transition from the Fermi energy to the top of valence band independent of temperature for this heavily Si-doped GaAsN, as with degenerate n-type GaAs. Because PL peak energy is expressed by the sum of bandgap energy, the increased energy of the Burstein-Moss effect, and the decreased energy of the bandgap narrowing, m(e)* is calculated to be 0.098 m(0) for this heavily Si-doped GaAsN with nitrogen composition of 0.6%, where m(0) is the electron mass. This result agrees well with previous studies, meaning that the method for estimation of m(e) is effective for dilute GaAsN.