Effect of built-in electric field in photovoltaic InAs quantum dot embedded GaAs solar cell

Shang, Xiangjun; He, Jinmei; Wang, H. L.; Li, M. F.; Zhu, Yaxing; Niu, Zhichuan; Fu, Ying

doi:10.1007/s00339-010-6152-8

Cited by 23 publications

(19 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1 and 2(a), is in the optical range of 500-900 nm above the GaAs bandgap, which predominantly determines the total PC of our samples in the photovoltaic I-V characteristics. In our previous work, 10 the short-circuit current density J sc of sample A was shown to be about 30% higher than sample C. The same 30% enhancement is also obtained here by integrating and comparing the relative PCs in the inset of Fig. 1.…”

Section: à3supporting

confidence: 87%

See 1 more Smart Citation

Quantum-dot-induced optical transition enhancement in InAs quantum-dot-embedded p–i–n GaAs solar cells

Shang

et al. 2011

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

Photocurrents (PCs) of three p-i-n GaAs solar cells, sample A with InAs quantum dots (QDs) embedded in the depletion region, B with QDs in the n region, and C without QDs, were studied experimentally and theoretically. Above GaAs bandgap, the PC of A is increased, while B is decreased with respect to C, since in A, the QD-induced reflection of hole wave function increases its overlap with electron wave function so that the optical transition rate is enhanced, while carrier mobility in B is reduced due to QD-induced potential variations. Moreover, A and B have increased PCs in the sub-GaAs-bandgap range due to QD optical absorptions.

show abstract

Section: à3supporting

confidence: 87%

“…The wavelengths of QD PC peaks agree with their photoluminescence peaks. 10 The QD PC intensity decreases as the wavelength increases, implying an increasing difficulty to extract photocarriers from a low-energy QD level because of their long tunneling length, high tunneling barrier, and large thermal activation energy, see Fig. 3(b).…”

Section: à3mentioning

confidence: 99%

Quantum-dot-induced optical transition enhancement in InAs quantum-dot-embedded p–i–n GaAs solar cells

Shang

et al. 2011

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…Furthermore, for QWR doped samples, as a result of n-type Si δ-doping, the electrons will easily occupy the QWRs, and this leads to a strong local potential barrier around the QWRs. Thus, the electron mobility in the conduction band can be reduced as a result of variations of the local potential around the QWRs [11]. As a result, the J-V characteristics of these devices are worsened as evidenced by their larger ideality factors.…”

Section: N2d=1x10mentioning

confidence: 99%

“…Consequently, this allows QDs, which have a discrete delta-like density of states, to create the required intermediate band that has a separate quasi-Fermi level from the conduction and valence band of the semiconductor [9]. However, the incorporation of QDs leads to a reduction of the photoelectrical conversion efficiency (PCE) of QD IBSC due to the formation of strain and resulting dislocations which lead to the deterioration of the open-circuit voltage, Voc [10][11][12]. To increase the PCE of QD IBSC, insertion of -dopants into the QDs was proposed [13,14].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2016

View full text Add to dashboard Cite

show abstract

“…This idea has indeed gained some experimental support in recent years [4][5][6][7][8][9][10][11][12] . Quantum-dot-embedded p-i-n solar cells show higher quantum efficiency in near infrared range but their overall efficiency still is lower than the efficiency of similar devices without QDs [4][5][6][7][8][9][10][11][12] . On the theory side, models involving a single QD were formulated to describe the kinetics of transitions from and into the intermediate levels 13,14 .…”

mentioning

confidence: 99%

Intraband absorption in finite, inhomogeneous quantum dot stacks for intermediate band solar cells: Limitations and optimization

Bragar

Machnikowski

2012

Journal of Applied Physics

View full text Add to dashboard Cite

We present a theoretical analysis of intraband optical transitions from the intermediate pseudo-band of confined states to the conduction band in a finite, inhomogeneous stack of self-assembled semiconductor quantum dots. The chain is modeled with an effective Hamiltonian including nearest-neighbor tunnel couplings and the absorption under illumination with both coherent (laser) and thermal radiation is discussed. We show that the absorption spectrum already for a few coupled dots differs from that of a single dot and develops a structure with additional maxima at higher energies. We find out that this leads to an enhancement of the overall transition rate under solar illumination by up to several per cent which grows with the number of QDs but saturates already for a few QDs in the chain. The decisive role of the strength of inter-dot coupling for the stability of this enhancement against QD stack inhomogeneity and temperature is revealed.One of the ways to improve the efficiency of solar cells is to introduce an intermediate band in the energy spectrum of a photovoltaic structure 1,2 . In this way, electrons can be sequentially promoted from the valence band to the intermediate band and then to the conduction band by absorbing photons with energies below the band gap which are not converted into useful electrochemical energy in a standard structure. As an implementation of this concept, a stack of quantum dots (QDs) in the intrinsic region of a p-i-n junction solar cell has been proposed 3 . This idea has indeed gained some experimental support in recent years 4-12 . Quantum-dot-embedded p-i-n solar cells show higher quantum efficiency in near infrared range but their overall efficiency still is lower than the efficiency of similar devices without QDs 4-12 . On the theory side, models involving a single QD were formulated to describe the kinetics of transitions from and into the intermediate levels 13,14 . On the other hand, modeling of the electron states and optical absorption in chains and arrays of QDs has been mostly limited to infinite, periodic superlattices of identical dots [15][16][17][18][19][20] . As we have shown recently 21 , enhanced absorption can appear also in finite chains of non-identical QDs but it is suppressed if the inhomogeneity of the QD chain (leading to non-identical electron ground state energies in the individual QDs) becomes too large. Since the actual QD chains are always finite (usually built of several to a few tens of QDs)4-12 and unavoidably inhomogeneous it is of large practical importance for the optimal design of intermediate band photovoltaic devices to extend the theoretical analysis to such more realistic structures.In this paper, we study the intraband optical absorption associated with the electron transition from the states confined in a finite stack of quantum dots to the conduction band. (Fig. 1) We propose a relatively simple and computation-effective model which, however, includes all the essential features of the system, in particular the inhomogeneity of the e...

show abstract

Effect of built-in electric field in photovoltaic InAs quantum dot embedded GaAs solar cell

Cited by 23 publications

References 19 publications

Quantum-dot-induced optical transition enhancement in InAs quantum-dot-embedded p–i–n GaAs solar cells

Quantum-dot-induced optical transition enhancement in InAs quantum-dot-embedded p–i–n GaAs solar cells

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

Intraband absorption in finite, inhomogeneous quantum dot stacks for intermediate band solar cells: Limitations and optimization

Contact Info

Product

Resources

About