Abstract
We have studied the structural, optical, and electrical properties of thermally evaporated, Cu-doped, ZnTe thin films as a function of Cu concentration and post-deposition annealing temperature. X-ray diffraction measurements showed that the ZnTe films evaporated on room temperature substrates were characterized by an average grain size of 300Å with a (111) preferred orientation. Optical absorption measurements yielded a bandgap of 2.21 eV for undoped ZnTe. A bandgap shrinkage was observed for the Cu-doped films. The dark resistivity of the as-deposited ZnTe decreased by more than three orders of magnitude as the Cu concentration was increased from 4 to 8 at.% and decreased to less than 1 ohm-cm after annealing at 260°C. For films doped with 6–7 at.% Cu, an increase of resistivity was also observed during annealing at 150–200°C. The activation energy of the dark conductivity was measured as a function of Cu concentration and annealing temperature. Hall measurements yielded hole mobility values in the range between 0.1 and 1 cm2/V·s for both as-deposited and annealed films. Solar cells with a CdS/CdTe/ZnTe/metal structure were fabricated using Cudoped ZnTe as a back contact layer on electrodeposited CdTe. Fill factors approaching 0.75 and energy conversion efficiencies as high as 12.1% were obtained.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
C. Ferekides, J. Britt, Y. Ma and L. Killian,Proc. 23rd IEEE Photovoltaic Specialist Conf. (1993), p. 389.
B.E. McCandless, Y. Qu and R.W. Birkmire,1994 IEEE First World Conf. Photovoltaic Energy Conversion, (1994), p. 107.
P.V. Meyers,Polycrystalline Cadmium Telluride n-i-p Solar Cell, Annual Report to SERI under Subcontract No. ZL-7- 06031-2 for the period of 6/1/87-8/31/88.
P.V. Meyers,Polycrystalline Cadmium Telluride n-i-p Solar Cell, Final Report to SERI under Subcontract No. ZL-7- 06031-2 (1990).
A. Mondai, R.W. Birkmire and B.E. McCandless,Proc. 22nd IEEE Photovoltaic Specialist Conf., (1991), p. 1126.
T.A. Gessert and T.J. Coutts,Proc. 12th NREL Photovoltaic Review Meeting, Denver, CO, October 1993,AIP Conf. Proc, (1994), pp. 306, 345.
R.G. Bohn, C.N. Tabory, C. Deak, M. Shao and A.D. Compaan,1994 IEEE First World Conf. Photovoltaic Energy Conversion, (1994), p. 354.
T.A. Gessert, X. Li, T. J. Coutts, A.R. Mason and R.J. Matson,J. Vac. Sci. Technol. A 12, 1501 (1994).
T.A. Gessert, A.R. Mason, R.C. Reedy, R. Matson, T.J. Coutts and P. Sheldon,J. Electron. Mater., to be published.
K.N. Raju, R.P. Vijayalakshmi, R. Venugopal, D.R. Reddy and B.K. Reddy,Mater. Lett. 13, 336 (1992).
S. Ako, S. Hongo and H. Bo,Solid State Commun. 51, 235 (1984).
J.C. Inkson,J. Phys. C: Solid State Phys. 9, 1177 (1976).
T.L. Larsen, C.F. Varotto and D.A. Stevenson,J. Appl. Phys. 43, 172 (1972).
H. Tubota,Jpn. J. Appl. Phys. 2, 259 (1963).
M. Aven and B. Segall,Phys. Rev. 130, 81 (1963).
N. Romeo, G. Sberveglieri, L. Tarricone, J. Vidal and A. Wojtowicz,Phys. Stat. Sol. 47a, 371 (1978).
T.L. Chu, S.S. Chu, F. Firszt and C. Herrington,J. Appl. Phys. 59, 1259 (1986).
A. Waxman, V.E. Henrich, F.V. Shallcross, H. Borkan and P.K. Weimer,J. Appl. Phys. 36, 168 (1965).
D. de Nobel,Philips Res. Rep. 14, 430 (1959).
D. Kim, S. Pozder, B. Qi, Y. Zhu, T.E. Furtak, D.L. Williamson and J.U. Trefny,12th NREL Photovoltaic Program Review, eds. R. Noufi and H.S. Ullal, (AIP Conf. Proc. 306), p. 320.
D. Mao, L. Feng, J. Tang, D.L. Williamson and J.U. Trefny, to be published.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Feng, L., Mao, D., Tang, J. et al. The structural, optical, and electrical properties of vacuum evaporated Cu-doped ZnTe polycrystalline thin films. J. Electron. Mater. 25, 1422–1427 (1996). https://doi.org/10.1007/BF02655377
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02655377