Dependence of quantum dot photocurrent on the carrier escape nature in InAs/GaAs quantum dot solar cells

Abstract

This paper presents a theoretical study of the effect of the nature of the carrier escape from quantum dots (QDs) on the performance of InAs/GaAs QD solar cells (QDSCs), based on numerical simulations. Excitonic and non-excitonic dynamics of electrons and holes are considered in the modeling, by assuming identical or separate time constants for the intersubband carrier transfer processes in the ground and excited states. It is shown that the excitonic capture and escape allow us to explain the non-additive characteristic of the QD photocurrent, observed when the total photocurrent of the cell is much lower than the sum of the photocurrents contributed separately by the barrier and the nanostructures. This behavior is practically eliminated in the non-excitonic case. The correlated dynamics under the nonexcitonic scenario is analyzed by calculating the device sensitivity to small changes introduced in the escape time of electrons. It is stated that the non-variation of the QD photocurrent with this parameter could be interpreted as a consequence of either a correlated electron-hole escape from QDs, or a dominant recombination over the other involved processes. The ideality factor of the different QDSCs studied is also calculated from simulations under both concentrated sunlight and dark conditions. The obtained results are in line with experimental measurements published in the literature.

Defect influence on in-plane photocurrent of InAs/InGaAs quantum dot array: long-term electron trapping and Coulomb screening

“…In(Ga)As quantum dots (QDs) are actively researched nanostructures for photonic and electronic devices with novel functionalities [1][2][3][4][5], advanced energy-efficient 'green' communication systems with ultra-large bit rate and energy-efficient lasers [6,7] or QD optical amplifiers [1], solar cells [8][9][10], singlephoton emitters [11][12][13], and quantum information processing or novel memory cells based on single QD [14][15][16].…”

Bipolar Effects in Photovoltage of Metamorphic InAs/InGaAs/GaAs Quantum Dot Heterostructures: Characterization and Design Solutions for Light-Sensitive Devices

“…In the last two decades, composite materials containing semiconductor nanostructures have found great use in photonic applications due to light sensitivity, ease and low cost of fabrication, spectral tunability, and highly efficient emission with short lifetime [ 1 – 5 ]. In(Ga)As quantum dot (QD) heterostructures is an important class of infrared-sensitive nanostructures, which has been widely employed in various photonic devices, such as lasers [ 2 , 6 ], single-photon sources [ 7 , 8 ], photodetectors [ 9 – 13 ], and solar cells [ 14 – 16 ]. Numerous investigations have been devoted to improve the photoelectric properties of such light-sensitive devices.…”

Recombination rates of the double quantum dot solar cell structure

“…Table 2 states the absorption coefficients of different layers of the DQDSC system, which are calculating using the relation of the absorption coefficient in [18,21] after the energy level calculation for the DQD structure as described in [22]. Table 3 gives relaxation time in the QDSC system; they cover the experimental results [4,12]. The work simulation is by MAOUD-37 under MATLAB environment [22,23], our laboratory software.…”

“…Electron and hole dynamics are modeling as excitonic and non-excitonic behavior in InAs/GaAs QDSCs. The non-additive behavior for QD and the barrier in the photocurrent is eliminated in the individual electron-hole behavior [4]. Foroutan and Baghban use metal nanoparticles for photocurrent increment in the GaAs QDSCs [5].…”