A theoretical model of an electron tunneling current in an anisotropic Si/Si 1−x Ge x /Si heterostructure was developed. The parallel and perpendicular kinetic energies were coupled and the coupling was included in expressing the electron transmittance through the anisotropic heterostructure. The model was applied to the anisotropic Si(1 1 0)/Si 0.5 Ge 0.5 /Si(1 1 0) heterostructure with a 25 nm thick strained Si 0.5 Ge 0.5 potential barrier, in which each layer of the heterostructure has three valleys (valleys 1, 2 and 3) with different inverse effective mass tensors and a conduction band discontinuity of 216 meV. The Si(1 1 0)/SiGe structure implies that only the four equivalent valleys (valleys 1 and 2) are considered in calculations. It was found that the transmittance for valley 1 is the same as that for valley 2 due to the same barrier height. The transmittance decreases as the electron phase velocity increases because the electron phase velocity enhances the barrier height. Moreover, the total tunneling current density for the phase velocity higher than 3 × 10 5 m s −1 differs significantly from that obtained without including the kinetic energy coupling. As the electron phase velocity gets higher, the total tunneling current density lowers. This implies that the coupling effect cannot be ignored for electrons with high phase velocity. drift-diffusion, energy-transport, hydrodynamic transport and quantum transport, are available in modeling devices based on the heterostructure. However, by now, the most popular model is the drift-diffusion transport model [5][6][7].With shrinking device dimensions, quantum effects become more pronounced and must be taken into account. An analytic expression for a tunnel current at an abrupt semiconductor-semiconductor heterojunction has been derived by assuming that the longitudinal and transverse components of electron motion are decoupled and the
Constructing student’s scientific literacy is still a challenge for the developing country. PISA 2015 report on scientific literacy showed that Indonesia was positioned at 62th out of 70 countries. According to this result, the students are only able to explain the simple science phenomenon because some learning activities have not followed good scientific inquiry as a fundamental aspect of the nature of science. To overcome the problem, PISA 2015 stated that teachers are suggested to design well-structured laboratory activities that make actual scientific concepts and ideas, and help students make the connection among the hands-on activities, scientific ideas and real-life problems. Moreover, the student’s conception of the nature of scientific knowledge is required to help a student become a scientifically literate person. This work aims to construct science knowledge and contextual problems to support students’ conception of the nature of science. In the case of the physics subject, eight new heat and temperature experiment designs are proposed to construct students’ scientific literacy in high schools. The aspects of scientific literacy on experiment designs are developed based on PISA 2015 frameworks.
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