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SIRKELI, Vadim; VATAVU, Sergiu; YILMAZOGLU, Oktay; KUPPERS, Franko; HARTNAGEL, Hans Ludwig. Quantum electron transport in non-polar ZnMgO/ZnO structures. In: Materials Science and Condensed Matter Physics. Ediția a 9-a, 25-28 septembrie 2018, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2018, p. 329.
|Materials Science and Condensed Matter Physics
Ediția a 9-a, 2018
Conferința "International Conference on Materials Science and Condensed Matter Physics" |
Chișinău, Moldova, 25-28 septembrie 2018
Compact solid-state sources are key components of various terahertz applications. Among electronic devices, resonant tunneling diodes (RTDs) and quantum cascade structures are promising as one of the candidates for terahertz wave generation and amplification at room temperature . The increasing of the output power of RTD devices at THz frequencies and increasing the operation frequency are crucial tasks. To solve these issues, II-VI compounds are considered as promising materials for high-power terahertz emitter devices due to the higher breakdown voltages and higher conduction band offset (CBO). In this paper, we report on a numerical study of the quantum electron transport in the non-polar m-plane ZnMgO/ZnO structures employing design scheme with two-well and three quantum barriers as shown in Fig. 1(a). This device consists of two ZnO quantum wells and three Zn0.85Mg0.15O quantum barriers with layer thicknesses starting from the left quantum barrier in nm are: 2.7/6.0/2.6/4.0. The temperature was varied from 100 K to 300 K. The cross section area of all investigated structures is 1 μm × 1 μm. The electronic quantum transport of non-polar m-plane ZnMgO/ZnO structures was investigated numerically within single band effective mass approximation using nextnano.MSB solver software. The details of the model used in this work can be found in Ref. . The material parameters used were taken from Ref. . Temperature dependence of current density-voltage characteristics of non-polar m-plane ZnMgO/ZnO structures is shown in Fig. 1(b). It could be seen that the current density-voltage characteristics show the clear resonance peaks and have the regions of negative differential resistance in temperature range from 100 to 300 K. At room temperature this resonant feature exhibits the maximum peak current density of ~ 3.5 kA/cm2 and the current density peak-to-valley ratio of ~ 8.2. Using the small-signal equivalent circuit model for a RTD device  we have estimated the maximum intrinsic frequency of oscillation fmax to be ~ 1.9 THz with a maximum of output power of ~ 70 nW at room temperature.