Band filling effects on temperature performance of intermediate band quantum wire solar cells

Abstract

Articles you may be interested inInGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells Appl. Phys. Lett. 105, 083124 (2014); 10.1063/1.4894424 Theoretical analysis of GaAs/AlGaAs quantum dots in quantum wire array for intermediate band solar cell Detailed studies of solar cell efficiency as a function of temperature were performed for quantum wire intermediate band solar cells grown on the (311)A plane. A remotely doped one-dimensional intermediate band made of self-assembled In 0.4 Ga 0.6 As quantum wires was compared to an undoped intermediate band and a reference p-i-n GaAs sample. These studies indicate that the efficiencies of these solar cells depend on the population of the one-dimensional band by equilibrium free carriers. A change in this population by free electrons under various temperatures affects absorption and carrier transport of non-equilibrium carriers generated by incident light. This results in different efficiencies for both the doped and undoped intermediate band solar cells in comparison with the reference GaAs p-i-n solar cell device. V C 2014 AIP Publishing LLC.

Investigation of electrically active defects in InGaAs quantum wire intermediate-band solar cells using deep-level transient spectroscopy technique

“…In addition, the C-V measurements at T=20 K revealed plateaux in QWR undoped devices which were related to 2DEG or/and the carrier accumulation in the QD layer, and for the QWR doped devices the i th steps observed in the C-V plots were related to the depletion of the i th QWR in the devices. The efficiency and EQE characteristics obtained by Kunets et al [15] at different temperatures correlated with the appearance of trap peaks observed in the DLTS and…”

“…The integrated GaAs EQE measurements showed an obvious U-shape trend as a function of temperature for QWR undoped devices, however, for the reference PIN devices the GaAs EQE characteristics were almost temperature independent. In this study [15], this behaviour can be associated to the electrically active traps E2 QWR and E3 QWR since they were detected within the temperature ranges where the solar conversion efficiencies were low. Although the PIN and QWR undoped devices have similar defects in terms of activation energy, the capture cross-sections of the QWR undoped devices are higher.…”

“…In addition, QWRs are expected to have applicable life-time of photogenerated carriers [17]. Kunets et al [7,15] also studied the effects of n-type Si delta doping on the external efficiency of this QWRs-based IB solar cell structure. They observed that at room temperature the solar energy conversion efficiencies of the reference p-n junction and p-i-n solar cell samples were 4.1 and 4.5%, respectively, whereas samples with incorporated QWRs and delta doping showed an increase of the efficiency up to 5.1% and 5%, respectively.…”

“…Hence, this will enhance the infrared (IR) absorption and the photocurrent in QD IBSC [13,14]. Kunets et al [7,15] used the above principle to fabricate an IBSC device consisting of one dimensional InGaAs quantum wires (QWRs) structure instead of using zero-dimensional quantum dots (QDs) or two-dimensional quantum wells (QWs). The QWRs were inserted into a GaAs p-i-n junction.…”

“…In this work, a detailed investigation is carried out on electrically active defects in a set of (311)A GaAs solar cell structures gown by molecular beam epitaxy (MBE) [7,15]. The devices investigated are p-n (labelled PN, first reference sample), p-i-n (labelled PIN, second reference sample), undoped p-i-n with InGaAs quantum wires (labelled QWR undoped) and Si -doped p-i-n with InGaAs quantum wires (labelled QWR doped).…”