Molecular-beam epitaxy and characteristics of GaN_(y)As_(1-x-y)Bi_(x)

摘要

GaN_(y)As_(1-x-y)Bi_(x) alloys were grown by molecular-beam epitaxy using solid Ga, Bi, and As sources and nitrogen radicals generated from nitrogen gas in rf plasma. Changing the growth temperature is found to be a convenient method for controlling the GaBi molar fraction in the alloy reproducibly. The photoluminescence (PL) spectra show that the PL peak energy of GaN_(y)As_(1-x-y)Bi_(x) alloy decreased with increasing GaBi and GaN molar fractions. The redshift coefficients of approx62 meV/(percent)Bi and approx130 meV/(approx)N at the PL peak energy of GaN_(y)As_(1-x-y)Bi_(x) were observed at room temperature. The temperature dependence of the PL peak energy in the temperature range of 150-300 K is much smaller than the temperature dependence of the band gap of InGaAsP. The temperature coefficients of GaAs_(1-x)Bi_(x) and GaN_(y)As_(1-x-y)Bi_(x) band gaps are governed by the GaBi molar fraction and they decrease with increasing GaBi molar fraction. GaN_(y)As_(1-x-y)Bi_(x) alloys with different PL peak energies and lattice matched to GaAs substrates were obtained. The photoluminescence peak energy was located at a predicted wavelength for the sample lattice matched to GaAs which was found to have the structure of Ga(N_(0.33)Bi_(0.67))_(z)As_(1-z).