混晶GaAs_(1-x)P_x∶N(x=0.4)中的N_X和N_Γ发光带的研究

Study on N X and N Γ Luminescence in GaAs 1- x P x ∶N( x =0.4) Alloys

本文采用变温条件下的光致发光谱和选择激发发光谱对混晶ＧａＡｓ１－ｘＰｘ∶Ｎ（ｘ＝０．４）中的ＮＸ和ＮΓ发光带进行了研究．在选择激发条件下，实验未观察到混晶ＧａＡｓ１－ｘＰｘ∶Ｎ（ｘ＝０．４）中ＮΓ→ＮＸ的带间能量转移现象．从变温光致发光谱得到在温度Ｔ＜５０Ｋ时，ＮΓ和ＮＸ的激活能分别为Ｅａ（ＮΓ）＝５．８ｍｅＶ和Ｅａ（ＮＸ）＝１１．２ｍｅＶ；在温度Ｔ＞５０Ｋ时，ＮΓ和ＮＸ的激活能分别为Ｅａ（ＮΓ）＝６７ｍｅＶ和Ｅａ（ＮＸ）＝３２ｍｅＶ．根据实验结果，我们提出，ＮＸ和ＮΓ中心分别来自孤立Ｎ中心和Ｎ束缚激子分子的发光．

Abstract We have performed a PL research on the N X and N Γ band in GaAs 1- x P x ∶N( x =0.4) samples at low temperature. The experimental results show that there does not exist any N Γ→N X interband energy transfer process in GaAs 1- x P x ∶N( x =0.4) samples. In the temperature region T <50K, the activation energy of N X and N Γ bands are E a(N X)=11 2meV and E a(N Γ)=5 8meV, respectively. In the temperature region T >50K, the activation energy of N X and N Γ bands are 32meV and 67meV, respectively. According to experimental results and analysis, a model in which N X band comes from isolated N X centers and N Γ band comes from N X bound exciton molecule is suggested.