tailieunhanh - Báo cáo hóa học: " Nonlinear dynamics of non-equilibrium holes in p-type modulation-doped GaInNAs/GaAs quantum wells"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Nonlinear dynamics of non-equilibrium holes in p-type modulation-doped GaInNAs/GaAs quantum wells | Khalil et al. Nanoscale Research Letters 2011 6 191 http content 6 1 191 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Nonlinear dynamics of non-equilibrium holes in p-type modulation-doped GaInNAs GaAs quantum wells Hagir Mohammed Khalil 1 Yun Sun1 Naci Balkan1 Andreas Amann2 Markku Sopanen3 Abstract Nonlinear charge transport parallel to the layers of p-modulation-doped GaInNAs GaAs quantum wells QWs is studied both theoretically and experimentally. Experimental results show that at low temperature T 13 K the presence of an applied electric field of about 6 kV cm leads to the heating of the high mobility holes in the GaInNAs QWs and their real-space transfer RST into the low-mobility GaAs barriers. This results in a negative differential mobility and self-generated oscillatory instabilities in the RST regime. We developed an analytical model based upon the coupled nonlinear dynamics of the real-space hole transfer and of the interface potential barrier controlled by space-charge in the doped GaAs layer. Our simulation results predict dc bias-dependent selfgenerated current oscillations with frequencies in the high microwave range. Introduction During the past decade dilute nitrides particularly the quaternary material system of GaInNAs GaAs have attracted a great deal of attention both because of unusual physical properties and potential applications for a variety of optoelectronic devices. The addition of a small amount of nitrogen induces a strong perturbation in the conduction band of matrix semiconductors while having a negligible effect on the valence band. As a result the electron mobility is greatly lowered and the hole mobility can become higher than the electron mobility in materials with relatively high nitrogen content. High hole mobility coupled with the low hole confinement energy 110 meV in our calculation for the samples investigated in this study 1 in the GaInNAs GaAs quantum well QW .