CAJ | 학술논문

用光的反射光谱和光的光致发光光谱的测量对Ga0.69In0.31NxAs1-x/GaAs 的单量子阱的光学特性作了研究,在单量子阱的反射光谱中,观察到 GaAs 能隙之上的 Franz-Keldysh 振荡和来源于量子阱区的各种类激子跃迁,Franz-Keldysh 振荡确定量子阱的内建电场并发现它是随 N 的浓度增加而增加;反射信号随样品中氮耦合增强而减弱,因为温度降低时载流子的定域作用导致调制效应的弱化.激子跃迁的能量和温度关系按照 Varshni 和爱因斯坦一玻司方程作了研究,在 PL 谱中观察到的 11H 跃迁能量和谱线展宽的温度反常关系解释为起源于氮耦合所引起的定域态,这种样品的谱线特征为随氮成份增加出现红移,氮结合作用的另一个结果是晶体的性质严重退化,明显地表现线宽受温度的影响增大.总之,氮引进系统会观察到GaAs 边带以上的 FkO 导致内建场增大,有低温时高激发态叠加并屏闭在定域态上的部分调制外场作用的倾向.PL 峰能量和线宽对温度的反常关系可以理解为由氮的结合作用引起的形成定域态和去除定域态的竞争结果.
용광적반사광보화광적광치발광광보적측량대Ga0.69In0.31NxAs1-x/GaAs 적단양자정적광학특성작료연구,재단양자정적반사광보중,관찰도 GaAs 능극지상적 Franz-Keldysh 진탕화래원우양자정구적각충류격자약천,Franz-Keldysh 진탕학정양자정적내건전장병발현타시수 N 적농도증가이증가;반사신호수양품중담우합증강이감약,인위온도강저시재류자적정역작용도치조제효응적약화.격자약천적능량화온도관계안조 Varshni 화애인사탄일파사방정작료연구,재 PL 보중관찰도적 11H 약천능량화보선전관적온도반상관계해석위기원우담우합소인기적정역태,저충양품적보선특정위수담성빈증가출현홍이,담결합작용적령일개결과시정체적성질엄중퇴화,명현지표현선관수온도적영향증대.총지,담인진계통회관찰도GaAs 변대이상적 FkO 도치내건장증대,유저온시고격발태첩가병병폐재정역태상적부분조제외장작용적경향.PL 봉능량화선관대온도적반상관계가이리해위유담적결합작용인기적형성정역태화거제정역태적경쟁결과.
The optical properties of Ga0.69In0.31NxAs1-x/GaAs single quantum well (SQW) structures have been studied using photoreflectance (PR) and photoluminescence (PL) measurements. In the PR spectra of single quantum well (SQW) samples, clear Franz-Keldysh oscillations (FKOs) above the GaAs band edge and the various excitonic transitions originating from the quantum well (QW) region have been ob-served. The built-in electric field in the SQW has been determined from FKOs and found to increase with N concentration. The PR signal has been found to decrease for nitrogen incorporated samples when the temperature was lowered due to a weakening of the modulation efficiency induced by carrier localization.The temperature dependence of the exciton transition energies have been studied in terms of both the Varshni and Bose-Einstein equations. The temperature dependence analysis yields information on the pa- rameters that describe the temperature variations of the interband transitions. The anomalous temperature dependent 11H transition energy and linewidth observed in the PL spectra have been explained as origina-ting from the localized states as a result of nitrogen incorporation. The spectral features of these samples showed red shift with increasing N composition x. Another consequence of N-incorporation is the severe degradation of the crystal quality as evidenced by a significant increase in the temperature independent broadening parameter. In addition, introducing N into the system also resulted in an increase in the built-in electric field as determined from the observed FKOs above the GaAs band edge which tends to increase the overlap integrals of the higher excited states as well as partially screening out the modulating external field on the localized states at low temperature. The anomalous behavior of the temperature dependence of the PL peak energy and the full width at half maximum (FWHM) can be understood as a result of competition between the delocalized states and the localized states induced by N-incorporation.