Abstract
Indium-alloyed diodes made from phosphorus-doped p-type ZnTe (carrier densities ∼2∼5×1017/cm3) showed electroluminescence when biased either in forward or reverse directions at liq. N2 temperature. In each case, emission spectra consisted of two bands, green and red. The narrow green band was at 540 mµ and the broad red one extended from 580 to 700 mµ, the former being attributed to phosphorus acceptors and the latter to indium donors. There were three features in the emission spectra, which distinguished forward and reverse biased electroluminescence from each other. These features suggest the difference in the excitation mechanisms between the two cases, forward and reverse cases corresponding to injection and breakdown respectively in metal-semi=insulator-semiconductor junction. Close similarity between the structures of the spectra of forward biased electroluminescence and that of photoluminescence is a strong support to the assumptions concerning the origin of the green electroluminescene band. Super-linear increase of emission intensity with increasing diode current in forward biased electroluminescence is interpreted on a M–SI–SC model.