Role of n-ZnO Layer on the Improvement of Interfacial Properties in ZnO/InGaN p-i-n Solar Cells

Abstract

InGaN has been predicted to be an efficient photovoltaic material. However, the high-density polarization charges and large potential barrier at the i-InGaN/n-GaN interface create an electric field that severely decreases the collection efficiency of p-InGaN/i-InGaN/n-GaN heterostructure solar cells. We demonstrate that, according to numerical simulations, utilizing a p-InGaN/i-InGaN/n-ZnO heterostructure can greatly reduce the piezoelectric field in the absorption layer and reduce the potential barrier between the n-type layer and the absorption layer interface, thus improving the performances of the solar cell. Moreover, we studied the influence of the band alignment on the ZnO/InGaN interface on the performance of the solar cell. We found that the band alignment of the ZnO/InGaN interface can keep the solar cells at a very high efficiency over a wide scope.

Keywords

Polarization effect / Heterostructure solar cell / Numerical simulations / Band alignment

References

[1] Wu JQ. When group-III nitrides go infrared: new properties and perspectives. J Appl Phys, 2009, 106(1): 011101

[2] Jani O, Ferguson I, Honsberg C, et al. Design and characterization of GaN/InGaN solar cells. Appl Phys Lett, 2007, 91(13): 132117

[3] Wu J, Walukiewich W, Yu KM, et al. Superior radiation resistance of In_1−xGa _xN alloys: a full-solar-spectrum photovoltaic materials system. J Appl Phys, 2003, 94(10): 6477-6482.

[4] Nanishi Y, Satio Y, Yamaguchi T. RF-molecular beam epitaxy growth and properties of InN and related alloys. J Appl Phys, 2003, 42(5A): 2549-2559.

[5] Vazquez M, Algora C, Rey-Stolle I, et al. III-V concentrator solar cell reliability prediction based on quantitative LED reliability data. Prog Photovolt, 2007, 15(6): 477-491.

[6] Neufeld CJ, Toledo NG, Cruz SC, et al. High quantum efficiency InGaN/GaN solar cells with 2.95 eV band gap. Appl Phys Lett, 2008, 93(14): 143502

[7] Xie S, Feng ZH, Liu B, et al. DC characteristics of lattice-matched InAlN/AlN/GaN high electron mobility transistors. Trans Tianjin Univ, 2013, 19(1): 43-46.

[8] Bhuiyan AG, Sugita K, Hashimoto A, et al. InGaN solar cells: present state of the art and important challenges. IEEE J Photovolt, 2012, 2(3): 276-293.

[9] Abell J, Moustakas TD. The role of dislocations as nonradiative recombination centers in InGaN quantum wells. Appl Phys Lett, 2008, 92(9): 091901

[10] Yu ET, Dang XZ, Asbeck PM, et al. Spontaneous and piezoelectric polarization effects in III-V nitride heterostructures. J Vac Sci Technol B, 1999, 17(4): 1742-1749.

[11] Chang JY, Kuo YK. Numerical study on the influence of piezoelectric polarization on the performance of p-on-n (0001)-face GaN/InGaN p-i-n solar cells. IEEE Electron Dev Lett, 2011, 32(7): 937-939.

[12] Kuo YK, Chang JY, Shih YH. Numerical study of the effects of hetero-interfaces, polarization charges, and step-graded interlayers on the photovoltaic properties of (0001) face GaN/InGaN p-i-n solar cell. IEEE J Quantum Electron, 2012, 48(3): 367-374.

[13] Xia Y, Brault J, Vennéguès P, et al. Growth of Ga- and N-polar GaN layers on O face ZnO substrates by molecular beam epitaxy. J Cryst Growth, 2014, 388: 35-41.

[14] Nam SY, Choi YS, Song YH, et al. n-ZnO/i-InGaN/p-GaN heterostructure for solar cell application. Phys Status Solidi A, 2013, 210(10): 2214-2218.

[15] Namkoong G, Diefeng G, Foe K, et al. Hybrid nitride-ZnO solar cells. ECS Trans, 2011, 41(4): 185-189.

[16] Inoue S, Katoh M, Kobayashi A, et al. Investigation on the conversion efficiency of InGaN solar cells fabricated on GaN and ZnO substrates. Phys Status Solidi RRL, 2010, 4(3/4): 88-90.

[17] Pantha BN, Sedhain A, Li J, et al. Electrical and optical properties of p-type InGaN. Appl Phys Lett, 2009, 95(26): 261904

[18] Nawaz M, Marstein ES, Hole A. Design analysis of ZnO/cSi heterojunction solar cell. IEEE Photovolt Spec Conf, 2010, 35: 2213-2218.

[19] IP KPS. Process development for ZnO-based devices, 2005, Gainesville: University of Florida.

[20] Lide DR. CRC handbook of chemistry and physics, 2004, Boca Raton: Chemical Rubber Publishing Company.

[21] Brown GF, Ager JW, Walukiewicz W, et al. Finite element simulations of compositionally graded InGaN solar cells. Sol Energy Mater Sol Cells, 2010, 94(3): 478-483.

[22] VurgaftmanI Meyer JR, Ram-Mohan LR. Band parameters for III-V compound semiconductors and their alloys. J Appl Phys, 2001, 89(11): 5815-5875.

[23] Look DC. Recent advances in ZnO materials and devices. Mater Sci Eng B, 2001, 80(1/3): 383-387.

[24] Wagner P, Helbig R. Hall effect and anisotropy and maneuverability of electron in ZnO. J Phys Chem Solids, 1974, 35(3): 327-335. in German)

[25] Wu J, Walukiewicz W, Yu KM, et al. Unusual properties of the fundamental band gap of InN. Appl Phys Lett, 2002, 80(21): 3967-3969.

[26] Li N. Simulation and analysis of GaN-based photoelectronic devices, 2005, Beijing: Chinese Academy of Sciences (in Chinese)

[27] Bandic ZZ, Bridger PM, Piquette EC, et al. Minority carrier diffusion length and lifetime in GaN. Appl Phys Lett, 1998, 72(24): 3166-3168.

[28] Chen F, Cartwright AN, Lu H, et al. Temperature dependence of carrier lifetimes in InN. Phys Status Solidi A, 2005, 202(5): 768-772.

[29] Fabien CAM, Doolittle WA. Guidelines and limitations for the design of high-efficiency InGaN single-junction solar cells. Sol Energy Mater Sol Cells, 2014, 130: 354-363.

[30] Fiorentini V, Bernardini F, Ambacher O. Evidence for nonlinear macroscopic polarization in III–V nitride alloy heterostructures. Appl Phys Lett, 2002, 80(7): 1204-1206.

[31] Della Sala F, Di Carlo A, Lugli P, et al. Carrier screening and polarization fields in nitride-based heterostructure devices. Phys B, 1999, 272(1/4): 397-401.

[32] Silvaco Inc. (2013) ATLAS user’s manual. http://www.silvaco.com. Accessed 02 Oct 2013

[33] Henry CH. Limiting efficiencies of ideal single and multiple energy gap terrestrial solar cells. J Appl Phys, 1980, 51(8): 4494-4500.