The correlation between the Peak of spontaneous spectra and the maximum of the injected carrier distribution in the energy band

the condition of the carrier distribution-maximum situated in the bandtail; the dependence of the carrier-distribution-maximum shifting-rate with injection level on the shape of the bandtail

and on whether or not the quasi-equilibrium distribution has been reached

have been analysed theoretically both under steady and transient cases.A new method for quantitatively determining the density-of-states distribution of the tail from the steady and transient emission spectra peak shifting is proposed. An important conclusion is that quansi-Fermi level do not exist during transient spontaneous emissions from GaAs doped with amphoteric silicon. Steady and transient time-resolved spectra from GaAs homojunction and heterojunc-tion samples doped with various dopants of different concentrations and different degrees of compensation

under various injection levels at 300 and 77K

are systematically measured. The experimental results agree well with the theoretical predictions

and on this qasis

the effect of bandtailing on the transient response time of spontaneous emission Is discussed.