Capacitance–voltage characteristics of InAs/GaAs quantum dots embedded in a pn structure

Abstract

We study the electronic states of self-organized InAs quantum dots embedded in a pn junction by means of capacitance–voltage (C–V) characteristics. A model based on the self-consistent solution of the Poisson equation and the drift-diffusion equations is proposed for calculating the capacitance. This model allows us to determine the energy levels of the quantum dot states and their inhomogeneous broadening from a comparison with experimental C–V data. Good quantitative agreement between predictions of the model and the low-frequency C–V characteristics is obtained.

Coulomb Damped Relaxation Oscillations in Semiconductor Quantum Dot Lasers

“…These have to be captured into the bound QD states before the laser transition can take place. Since in the lasing regime, the WL carrier density is very high, the capture processes are dominated by Coulomb scattering (nonlocal Auger recombination) [23], [25], [26], which is also supported by the modeling of QD transport experiments [27], [28]. Our approach also includes the electron-phonon scattering for the cooling process in the WL, but neglects it for scattering into the QD states.…”

Theory of Nonlinear Transport for Ensembles of Quantum Dots

“…Here we focus on quantum dot layers embedded in a pn-structure [10]. By comparing our simulations with experimental data, we are able to obtain information regarding the energy levels of the quantum dots and their inhomogeneous broadening [11], see Fig. 1.In simulating these curves the Coulomb interaction was treated within a mean field model and the energy levels were regarded as randomly distributed with a certain width fitted to the experiment.…”

“…Our model can be used to fit the energy levels. The inset demonstrates the sensitivity to varying the energy of the first excited electron state in the quantum dots (from [11]). …”

Deep Level Assessment of n-Type Si/SiO2Metal-Oxide-Semiconductor Capacitors with Embedded Ge Quantum Dots

“…Successful operation requires that the charge does not leak away by the assistance of traps or defects in the material stack or by thermally-assisted tunneling to the substrate. 6,7 In fact, QDs embedded in a semiconductor or oxide matrix behave in many aspects like giant traps, so that their defect levels can be studied by capacitance-voltage (C-V) measurements at different frequency (f) and temperature (T), [8][9][10][11][12] also called admittance spectroscopy 13,14 and by capacitance transient-based techniques, [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] like Deep-Level Transient Spectroscopy (DLTS). 14,33 This enables the assessment of hole and electron emission from the levels associated with QDs, revealing their energy position and capture cross section for thermally stimulated carrier processes.…”