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 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.国家自然科学基金;福建省自然科学基

The Phonon Sidebands of Excitons Bound to NN 1 Trap in GaAs 1-x P x ∶N( x = 0.88) Alloys

采用选择激发的实验手段，在混晶gAAS1-XPX∶n（X＝0.88）的光致发光谱中观察到nn1对束缚激子发光的声子伴线.通过荧光谱线窄化效应，在发光谱中得到与gAP∶n低温光致发光谱中A线相似的nn1线的声子伴线精细结构，其中包括TA，lA，lO等声子伴线.这个结果在实验上有力地证实了在混晶gAAS1-XPX∶n中的确存在着nn1发光中心.By using selective excitation technique, the phonon sideband of NN 1 pair emission is observed in GaAs 1-x P x ∶N( x = 0.88) alloys. Due to Fluorescence line narrowing, the Fine structure of phonon sidebands of NN 1 pair emission , which is very similar to that of A line in GaP∶N, including TA, LA, LO phonons, is distinguished.This result conFirms that the NN 1 centers do exist in GaAs 1-x P x ∶N alloys experimentally.国家和福建省自然科学基

The Transient Spectroscopic Study on Tenary GaAs 1-x P x ∶N Alloys

采用皮秒量级的超快速光谱技术，分析了混晶gAAS1-XPX∶n材料发光瞬态过程.结果证实了材料随组份变化，从间接带到直接带（XC＝0.45k，77k）转变的带增强效应.对nX发光带不同能量位置的发光衰退测量还表明nX带同时存在着快速的带内隧穿转移和较慢的发光衰退过程The pico second ultraFast spectroscopic technology is used to study the tenary GaAs 1-x P x∶ N alloys.The results conFirm the band structure enhancement eFFect in GaAs 1-x P x∶ N alloys.The PL decay measurements of N X band show that the Fast intraband tunneling and slow luminescent decay coexist in GaAs 1-x P x∶ N alloys.国家和福建省自然科学基金;中山大学超快速激光光谱学国家重点实验室资

NNi Emission in GaAs_(1-x)Px:N(x=0.88)under Low Excitation Power Density

在低激发动率密度条件下研究了混晶材料gAAS1-XPX：n（X＝0.88）中的nnI对束缚激子发光.发现随温度升高，在光致发光谱中依次出现nn3和nn1发光带，同时nX带明显热猝灭.在低温下，降低激发功率密度，nX谱带移向低能端并且窄化.结果表明，在低激发功率密度下，热激活的nX→nnI激子转移过程明显加强，激子转移的机制主要是变程跳跃过程.Abstract The NNi(i=1,3)emission in GaAs1-xPx:N with somewhat low composition x =0.88 under low excitation power density is observed For the First time.As temperature is raised, the NN3 and NN1 appear successively in CW spectrum,while the N.band quenches thermally.At low temperature,the narrowing and shiFt to lower energy of Nx band with decreasing of excitation power density are also observed.It is shown that the thermally activated Nx→NNi exciton transFer proceeds eFFiciently,and variable-range hopping mechanism is mainly responsible For transFer.国家自然科学基

THE PHONON SIDEBAND STRUCTURE ON N_X LUMINESCENCE IN GaAs_(1-x)P_x∶N ALLOYS

本文采用荧光窄化技术，对低组分的gAAS（1-X）PX∶n（X＝0.76，0.65）混晶材料中nX束缚激子的声子伴线进行了研究.在低温下，选择激发nX带时，我们得到了与gAP∶n低温发光谱中类似的声子伴线结构.根据实验结果，给出了混晶中各种声子的能量.另外，对组分为X＝0.76的gAAS（1-X）PX∶n混晶样品，我们还首次观察并分析了多声子重现光谱.luorescence line narrowing technology has been used to study the phonon sidebands of Nx-bound excitons in GaAs1-xPx: N in details.Under selective excitation into inhomogenously broadened Nx band at low temperature, the sharp phonon sidebands like those in low temperature PL spectrum For GaP: N are observed.According to the experimental results, we obtained the energy values of various phonons in GaAs1-xPx: N alloys with the composition x=0.76 and 0.65.The photoluminescence spectrum with periodically repeated phonon sideband structure For GaAs1-xPx: N (x=0.76) is observed and analyzed For the First time.国家和福建省自然科学基