Major challenges for InGaAs/GaAsP multiple quantum well (MQW) solar cells include both the difficulty in designing suitable structures and, because of strain-balancing requirement, growing high-quality crystals. The present paper proposes a comprehensive design principle MQWs that overcomes trade-off between light absorption and carrier transport is based, particular, on systematical investigation GaAsP barrier effects dynamics occur various widths heights. fundamental strategies related to...

Abstract Bandgap engineering of strain‐balanced InGaAs/GaAsP multiple quantum wells (MQWs) allows high‐quality materials with an absorption edge beyond GaAs to be epitaxially grown in Ge/GaAs‐based multijunction solar cells. We demonstrate MQW cells effective bandgaps ranging from 1.31 eV as low 1.15 eV. The bandgap‐voltage‐offset MQWs is found independent and superior a bulk reference by approximately 0.1 V. This implies the merit high photovoltage compared same bandgap addition their...

Voltage-loss analysis is essential in the development of next-generation solar cells, such as perovskite, chalcopyrite, kesterite, and nano/quantum-structured cells. provides valuable insights into how energy conversion efficiency cells can be enhanced. However, a comprehensive accurate method to evaluate voltage loss quantum-structured lacking. This study establishes demonstrates quantitative voltage-loss based on detailed balance theory. reveals relationship between external quantum...

Abstract Insertion of quantum wells (QWs) extends the absorption edge to a longer wavelength than value p-i-n cell without QWs, which is preferable for improved current matching InGaP/GaAs/Ge multijunction cell. The however, reduce open-circuit voltage ( V oc ) and degrade fill factor; latter significant large number QWs that are mandatory sufficient light absorption. As structure minimize these drawbacks, QW superlattice, strain-balanced In 0.13 Ga 0.86 (4.7 nm)/GaAs 0.57 P 0.43 (3.1 nm)...

We study light management in a 430 nm-thick GaAs p-i-n single junction solar cell with 10 pairs of InGaAs/GaAsP multiple quantum wells (MQWs). The epitaxial layer transfer on gold mirror improves absorption and increases the external efficiency below bandgap by factor four through excitation Fabry-Perot resonances. show good agreement optical simulation achieve around 10% conversion efficiency. demonstrate numerically that this promising result can be further improved anti-reflection layers....

Abstract This study investigated the effect of external luminescence efficiency on power generation characteristics thermoradiative diodes (TRDs). The was improved by converting a pn homojunction into heterojunction. Fabricated In0.53Ga0.47As and In0.53Ga0.47As/InP heterojunction TRDs were suspended inside shroud cooled to 70 K, TRD temperature varied from approximately 300 K 410 K. with high had maximum point 5 times that homojunction, we successfully demonstrated method for improving...

Abstract The semi-transparent type of photovoltaic (PV) cell consisting the ultra-thin GaAs was demonstrated. Applying grid shaped metal contact for both top- and rear-side interface extremely reducing an absorption thickness absorber layer to 100 nm in thickness, PV device transferred quartz substrate via epoxy resin indicated a significant optical transparency wavelength range. Compared with samples rear planer-type working as well backside reflector, reduction short circuit current...

The carrier collection efficiency (CCE) is proposed as an effective parameter for indicating the of transport in quantum nanostructured solar cells. CCE can be estimated by normalizing illumination-induced current enhancement to its saturation value at reverse bias. derivation procedure experimentally validated examining bias-dependence light absorption, and investigating balance between absorbed photons collected carriers effect AM1.5 bias-illumination characterization was also investigated...

Quantum wires (QWRs) form naturally when growing strain balanced InGaAs/GaAsP multi-quantum wells (MQW) on GaAs [100] 6° misoriented substrates under the usual growth conditions. The presence of instead could have several unexpected consequences for performance MQW solar cells, both positive and negative, that need to be assessed achieve high conversion efficiencies. In this letter, we study QWR properties from point view their as cells by means transmission electron microscopy, time...

Insertion of multiple quantum wells (MQWs) into the i-region GaAs p-i-n solar cells can shift effective bandgap to optimal value for single-junction under high sunlight concentration. The efficiency corresponding absorption by MQWs must be sufficiently achieving high-efficiency MQW cells. Here, we report light-trapping thin-film increasing photoabsorption in MQWs. In order suppress free-carrier loss and enhance light trapping, only active layers including were processed a cell flip-chip...

Abstract A quantum wire‐on‐well (WoW) structure, taking advantage of the layer undulation an InGaAs/GaAs/GaAsP superlattice grown on a vicinal substrate, was demonstrated to enhance carrier collection from confinement levels and extend lifetime (220 ns) by approximately four times more than planar reference superlattice. Strained superlattices were GaAs substrates under exactly same conditions except for substrate misorientation (0 6 ° off). The growth off induced significant as result step...

For a quantitative evaluation of the carrier transport dynamics multiple quantum well (MQW) solar cells, collection efficiency (CCE) was defined and its measurement procedure proposed. CCE is essentially normalized to saturation value at reverse bias. It allows us know whether substantial carriers are actually extracted any bias voltage, uncover bottleneck problems that emerge operation The advantage analysis photoexcited can be selectively examined independently diode characteristics...

The high aspect ratio (HAR) quantum well was proposed as a general design principle to overcome the tradeoff problem between light absorption and carrier collection in multiple quantum-well (MQW) solar cells. An HAR-MQW structure consists of thin wells barriers, its fundamental strategies are 1) thinner enhance for 1HH transition make it possible absorb same amount with MQW region; 2) barriers allow photogenerated carriers be extracted by means tunneling transport; 3) deeper obtain effective...

Hot-carrier solar cells offer the opportunity to harvest more energy than limit set by Shockley–Queisser model reducing losses due thermalization of photo-generated carriers. Previous reports have shown lower rates in thinner absorbers, but origin this phenomenon is not precisely understood. In work, we investigate a series ultrathin GaAs absorber layers sandwiched between AlGaAs barriers and transferred on host substrates with gold back mirror. We perform power-dependent photoluminescence...

A major challenge for multiple quantum well (MQW) solar cells is to extract sufficient photo-excited carriers an external circuit through the MQW region under forward bias. The present study reports effectiveness of compensation doping in i-region, which includes MQWs, more efficient transport both electrons and holes. Unintentional p-type background occurs GaAs by inevitable carbon incorporation during metal-organic vapor phase epitaxy, causing undesirable bending band lineup i-region...

Tunneling enhancement of cell performance in InGaAs/GaAsP multiple quantum well (MQW) solar cells has been studied to investigate the potential overcoming carrier collection problem, which hinders maximum structure cells. To accurately effects tunneling effect, study was carried out samples with different GaAsP barrier thickness, controlled absorption edge, and constant built-in field. The effect confirmed by evaluating escape times using time-resolved photoluminescence technique measuring...

Aiming at reducting in Joule energy loss of a photovoltaic cell under sunlight concentration, monolithic integration GaAs cells has been realized, which five subcells were connected series and the total surface area occupied over 80% whole chip area. Using plasma etching with Cl2, sufficiently sharp mesa for device isolation was obtained. Insulation between etched sidewalls interconnect electrodes proved to be most significant issues purpose eliminating shunt resistance securing reasonable...

Precise strain compensation for lattice-mismatched quantum wells is crucial obtaining high performance devices such as well solar cells. High-accuracy in situ curvature monitoring a more efficient tool to adjust growth conditions perfect balancing, and we have achieved measurement during of InGaAs/GaAsP multiple by metal organic vapor phase epitaxy. We also developed the calculation model taking into account thermal expansion lattice relaxation effects based on Stoney’s equation. The...

A quantum-well (QW) solar cell including InGaAs wells is a promising candidate for the purpose of current matching in InGaP/GaAs/Ge tandem cells by extending edge quantum efficiency to longer wavelengths. Even though QWs increase short-circuit extended effective band edge, they tend obstruct carrier transport and degrade cell. Therefore, superlattice (SL) structure has been proposed prevent recombination carriers inside and, more importantly, enable tunnel neighboring well, leading an...

We have observed photocurrent due to two-step photon absorption using an InGaAs/GaAsP strain-balanced quantum-well (QW) superlattice cell, with barrier thickness of 3 nm. Upon infrared irradiation a filtered air mass 1.5 light source (λ > 1.4 μm), quantum efficiency was increased by 0.8% at the wavelength range corresponding wells. No enhancement either for conventional QW solar cell thick (11 nm) barriers or GaAs pin suggesting that efficient separation photogenerated electrons and holes in...

For a quantitative evaluation of the carrier transport dynamics multiple quantum well (MQW) solar cells, collection efficiency ( CCE ) was defined and its measurement procedure proposed. is essentially normalized to saturation value at reverse bias. It allows us know whether substantial carriers are actually extracted any bias voltage, uncover bottleneck problems that emerge operation The advantage analysis photoexcited can be selectively examined independently diode characteristics devices...