摘要
用薛定谔方程和泊松方程自洽计算的方法研究了Al0.75Ga0.25N/GaN对称双量子阱(DQWs)中子带间跃迁(ISBT)的波长和吸收系数对中间耦合势垒高度、中间耦合势垒宽度、势阱宽度和势垒掺杂浓度的依赖关系.研究发现,第一奇序子带S1ood与第二偶序子带S2even ISBT波长随着中间耦合势垒高度的降低而变短.当中间耦合势垒高度高于0.62eV时,S1odd-S2even ISBT吸收系数随着中间耦合势垒的降低而增加.当减小AlxGa1-xN/GaN的DQWs中间耦合势垒宽度时,S1odd-S2even ISBT波长将变短,其吸收系数变大.另一方面,当对称DQWs的势阱宽度大于1.9nm时,S1odd-S2even ISBT波长随着势阱的变窄而减小,S1odd-S2even ISBT吸收系数随着势阱的变窄而增加.当势垒中的掺杂浓度小于1018/cm3时,S1odd-S2even ISBT波长基本不随掺杂浓度变化,而吸收系数随掺杂浓度的增加而增加.这些结果对于利用DQWs实现工作于光纤通信波段超快的、基于三能级或四能级系统的双色光电子器件的应用具有指导意义.
By solving the Schrodinger and Poisson equations self-consistently, the central barrier height, central barrier width, well width, and doping concentration in the barriers of symmetric Al0.75 Ga0.25 N/GaN double quantum wells （DQWs） have been studied to investigate their influences on the wavelength and absorption coefficient of intersubband transitions （ISBTs）. A smaller wavelength of the ISBT between the first odd and the second even order subbands （ S1odd-S2 ISBT） in Al0.75 Ga0.25 N/GaN DQWs and a larger absorption coefficient of the S1odd-S2even ISBT were obtained with decreased central barrier height, when the central barrier height was larger than 0.62 eV. The wavelength of the Slodd- S2even ISBT decreases, and the absorption coefficient of the Slodd-S2even ISBT increases, when the width of the central barrier is reduced. On the other hand, decreasing the width of the well will result in smaller wavelength of the S1odd-S2even ISBT and larger absorption coefficient of the Slodd-S2even ISBT when the width of the well is narrower than 1.9 nm. When doping concentration in the barriers is smaller than 10^18/cm^3, the wavelength of the S1odd-S2even ISBT is unchanged, while the absorption coefficient of the Slodd-S2even ISBT increases with the doping concentration. These results provide useful guidance for realization of ultrafast two-color optoelectronic devices operating in the optical communication wavelength range.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2008年第4期2386-2391,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:60325413)
国家重点基础研究发展规划(批准号:2006CB604908)
教育部科学技术研究重大项目(批准号:705002)
北京市自然科学基金(批准号:4062017)资助的课题~~
