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nnp:optics:optical_absorption_simple [2019/03/11 13:31] stefan.birner [Structure] |
nnp:optics:optical_absorption_simple [2021/07/22 17:38] (current) stefan.birner [Optics tutorial (Simple)] |
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====== Optics tutorial (Simple) ====== | ====== Optics tutorial (Simple) ====== | ||
This simple tutorial shows a simple simulation studies for absorption of semiconductor devices. | This simple tutorial shows a simple simulation studies for absorption of semiconductor devices. | ||
+ | (It seems that this tutorial is based on the file AlGaAs_QW_Frankenberger_nnp.in which has been documented here: [[https://www.nextnano.com/dokuwiki/doku.php?id=nnp:optics#part_3frankenberger|Optics tutorial]]) | ||
===== Structure ===== | ===== Structure ===== | ||
Line 43: | Line 44: | ||
</code> | </code> | ||
- | * ''interband'', ''intraband'' Initalizes, should it calculates the intra/interband transitions or not. | + | * ''interband'', ''intraband'' Initalizes if intra/interband transitions should be calculated or not. |
* ''polarization'' describes the polarization direction of the electric field. (When there is an 'i' it means it is circulary polarized) | * ''polarization'' describes the polarization direction of the electric field. (When there is an 'i' it means it is circulary polarized) | ||
- | * ''output_transitions'' Calculation of the transition matrix elements(yes/no) | + | * ''output_transitions'' Calculation of the transition matrix elements (''yes''/''no'') |
- | * ''occupation_threshold'', ''energy_threshold'' t, ''transition_threshold'' The minimum value of the (energy, | + | * ''occupation_threshold'', ''energy_threshold'', ''transition_threshold'' The minimum value of the energy, occupation and transition intensity of the transition which should be calculated. |
- | * ''occupation'', ''transition intensity'') of the transition which should be calculated. | + | * ''energy_min'', ''energy_max'' Boundaries of the calculated energy spectra. |
- | * ''energy_min'', ''energy_max'' Borders of the calculated energy spectra. | + | * ''energy_resolution'' The energy grid spacing of the calculated points in the energy space. |
- | * ''energy_resolution'' The spacing of the calculated points in the energy space. | + | |
* ''k_integration'' defines the points for integrating in the k space | * ''k_integration'' defines the points for integrating in the k space | ||
===== The output ===== | ===== The output ===== | ||
==== Bandedges in the sample ==== | ==== Bandedges in the sample ==== | ||
- | After it has calculated the strain, it calculates the the bandedges of the structure which can be seen on the figure: | + | After the strain has been calculated, the bandedges of the structure are determined which can be seen in the figure: |
{{ :nnp:optics:optics_simple_bandedges.png?600 |}} | {{ :nnp:optics:optics_simple_bandedges.png?600 |}} | ||
<caption> | <caption> | ||
- | The bandedges in the sample Conduction band HH, and LH bands SO band | + | The bandedges in the sample: Conduction band, heavy hole, light hole and split-off hole band edges |
</caption> | </caption> | ||
- | In the quantum well region it can be seen that the bandedge smaller, and the valence band edge is close to the fermi level. That is the reason, why the valence band is populated, and interband transition could happen. | + | In the quantum well region it can be seen that the bandedge is smaller, and the valence band edge is close to the Fermi level. |
+ | That is the reason why the valence band is populated and interband transition could happen. | ||
==== Quantum Mechanics ==== | ==== Quantum Mechanics ==== | ||
- | From the bandedges the program calculates the wavefunctions, in each band which is definied in the line: | + | From the bandedges the program calculates the wavefunctions in each band which is defined in the line: |
<code> | <code> | ||
num_electrons=$NumE | num_electrons=$NumE | ||
num_holes=$NumH | num_holes=$NumH | ||
</code> | </code> | ||
- | It means how many electron and hole states should be calculated. | + | Here you can specify how many electron and hole states should be calculated. |
The wavefunctons are plotted on the following figure: | The wavefunctons are plotted on the following figure: | ||
{{ :nnp:optics:optics_simple_wf_simple.png?600 |}} | {{ :nnp:optics:optics_simple_wf_simple.png?600 |}} |