Influence of proton implantation on the properties of CuInSe₂ single crystals (II)

Abstract

Copper deficient p-type conducting CuInSe, single crystals were implanted with 40 keV protons in the fluence range from 2.5. lOI4 to 1.5. 10l6 cm72. Over the whole fluence range the implanted layers were n-type conducting which is ascribed to passivation of the acceptors due to copper vacancies and formation of donors by hydrogen atoms located at interstitial positions. The thermal stability of the conductivity changes due to proton implantation is limited to temperatures below 100 "C.Kupferarme p-leitende CuInSe,-Einkristalle wurden mit Protonen der Energie von 40 keV im Dosisbereich von 2,5 . l O I 4 bis 1,5 . 10l6 cm-' implantiert. Die implantierten Schichten waren im gesamten Dosisbereich n-leitend, was einer Passivierung der durch Kupfervakanxen bedingten Akzeptoren und der Bildung von Donatoren durch auf Zwischengitterpliitzen eingebaute Wasserstoffatome zugeschrieben wird. Die thermische Stabilitat der durch die Protonenimplantation verursachten Leitfahigkeitsanderungen ist auf Temperaturen unterhalb 100 "C beschrankt.

Surface Engineering of CuIn_0.75Ga_0.25Se₂ Thin Films

“…However, post implantation heat treatments can alter these defects. In studying the influence of proton implantation on the electrical properties of p-type CIS single crystals, it has been observed that the implantation induced modifications become thermally unstable at temperatures close to or even below 100˚C [14]. It will be interesting to expand this study to ascertain the post-implantation annealing effects on properties of CIGS thin films.…”

“…The most probable cause for the observed change in band gap is due to the inclusion of shallow levels as discussed earlier. The incorporation of hydrogen into CIS single crystals using both proton implantation and diffusion from a plasma source has been found to considerably modify the electrical properties of the compound [14]. Thin film samples of CIGS already processed under various post deposition heat treatments were implanted with hydrogen species (10keV, 10 15 ions/cm 2 ) at room temperature.…”

“…Hydrogen has a tendency to interact with other intrinsic or extrinsic defects and induce defects in semiconductors [12]. It is well known that all hydrogenation techniques produce some lattice damage [14] which affects the native defect concentrations and thus the electrical and photo-thermal properties. However, post implantation heat treatments can alter these defects.…”

Optical Investigation of Defects in p‐type CuInSe2 Single Crystals

“…In the past two decades the parameters of the native defects governing the electrical properties of CuInSe2 single crystals and thin films have been extensively investigated (NEUMANN I986a; NEUMANN, TOMLINSON and references cited in these papers) with the result that the conductivity type and carrier concentration of the material can now be monitored with sufficient reliability by appropriate choice of growth conditions and post-growth annealing treatments. Furthermore, the trends observed in the electrical properties can be reasonably explained in terms of a relatively simple intrinsic point defect model (NEUMANN 1983(NEUMANN , 1986aYAKUSHEV et al). However, besides these shallow electrically active defects quite a number of different electrically inactive defects with deep states in the forbidden gap have been observed in CuInSe2 single crystals and thin films by deep level transient spectroscopy (ABOU-ELFOTOUH et al 1991 b, c;CHRISTOFOROU et al;HANAK et al; IGALSON, BACEWICZ; LI, S H I H ; M~L L E R , RODAK) and photoacoustic spectroscopy (ZEGADI et al 1992(ZEGADI et al , 1994(ZEGADI et al , 1995.…”

Interaction of Atomic Hydrogen with the Surface of Cu-llII-V12 Chalcopyrite Semiconductors-A Method for Controlled Stoichiometry Variation

“…A possible post-growth control of its concentration could be also of practical interest. Indeed, type conversion from p-to n-type has been found after 10 keV hydrogen implantation in p-type CuInSe 2 and attributed to either a copper vacancy passivation or a donor level of interstitial hydrogen [1]. The hydrogenation of compound semiconductors with a high hydrogen affinity of at least one component, however, is not easy to perform using common hydrogen plasma diffusion techniques.…”