GaP_(1-x)N_x混晶(x=0.24%～3.1%)发光复合机制的研究

Investigation on the Emission Recombination Mechanism of GaP_(1-x)N_(x) Alloys(x=0.24% ～3.1%)

利用变温光致发光(PL)谱研究了一系列GaP1-xNx混晶的发光复合机制.GaP1-xNx混晶的PL谱从低组分的NN对束缚激子及其声子伴线到高组分杂质带发光的特征,表现出明显的带隙降低的趋势.测量结果显示,在组分x≥0.24%的样品的发光谱中NN1能量之下已经开始出现几个新的束缚态,在低组分的混晶中,只存在一种激活能,仍然保持有束缚激子的特征;而在高组分样品(x≥0.81%)中存在两种激活能.高组分样品一方面仍保留有束缚激子的特征,另一方面也表现出新的发光机制.

This paper presented an investigation on the emission recombination mechanism of the novel GaP_(1-x)N_(x) alloys, using the temperature-dependent photoluminescence(PL) spectra. The GaP_(1-x)N_x alloys display obvious band-gap reduction characteristic, with the PL spectra developing from nitrogen bound excitons and their phonon replicas under low x composition to impurity band emission under high x composition. The results apparently indicate the appearance of several new bound states below the NN_1 bound exciton even when the composition x is as low as 0.24%. In low composition alloy, there is only one activation energy, which still remains the characteristic of bound exciton state. While in high composition alloy(x≥0.81%), there exist two kinds of activation energies. The samples with high composition, on one hand, still remain the bound exciton characteristic, on the other hand, display new recombination mechanism. Such new recombination might be related to NNN cluster or have certain interaction with the NN bound excitons.