CuInSe2 thin films produced by rf sputtering in Ar/H2 atmospheres

Structural, compositional, optical, and electrical properties of CuInSe2thin filmsgrown by rf reactive sputtering from a Se excess target in Ar/H2 atmospheres are presented. The addition of H2 to the sputtering atmospheres allows the control of stoichiometry of films giving rise to remarkable changes in the film properties. Variation of substrate temperature causes changes in film composition because of the variation of hydrogen reactivity at the substrate. Measurements of resistivity at variable temperatures indicate a hopping conduction mechanism through gap states for films grown at low temperature (100–250 °C), the existence of three acceptor levels at about 0.046, 0.098, and 0.144 eV above valence band for films grown at intermediate temperature (250–350 °C), and a pseudometallic behavior for film grown at high temperatures (350–450 °C). Chalcopyrite polycrystalline thin films of CuInSe2 with an average grain size of 1 μm, an optical gap of 1.01 eV, and resistivities from 10− 1 to 103 Ω cm can be obtained by adding 1.5% of H2 to the sputtering atmosphere and by varying the substrate temperature from 300 to 400 °C

Structural, electrical, and optical properties of CuGaSe2 rf sputtered thin films

Thin films of CuGaSe2 have been produced by rf sputtering. Compositional, structural, electrical, and optical properties are strongly influenced by growthtemperature. At substrate temperatures lower than 300 °C amorphous or poorly crystalline Se‐excess films are obtained, showing high resistivity (≊103 Ω cm) and optical transitions at 1.62, 1.80, and 2.4 eV (values lower than the single‐crystal counterparts). At the higher growthtemperatures,polycrystalline films are obtained (average grain size 0.7 μm) with lower values of resistivity (1 Ω cm), and optical transitions at 1.68, 1.90, and 2.55 eV (very close to the single‐crystal values). A hopping conduction mechanism has been detected at the lower measuringtemperature (T150 K). Structural and compositional characteristics are used to explain the behavior observed in the electrical and optical properties

Deposition of SiNx : H thin films by the electron cyclotron resonance and its application to Al/SiNx : H/Si structures

We have analyzed the electrical properties and bonding characteristics of SiNx:H thin films deposited at 200 degrees C by the electron cyclotron resonance plasma method. The films show the presence of hydrogen bonded to silicon (at the films with the ratio N/Si<1.33) or to nitrogen (for films where the ratio N/Si is higher than 1.33). In the films with the N/Si ratio of 1.38, the hydrogen content is 6 at. %. For compositions which are comprised of between N/Si=1.1 and 1.4, hydrogen concentration remains below 10 at. %. The films with N/Si=1.38 exhibited the better values of the electrical properties (resistivity, 6x10(13) Omega cm; and electric breakdown field, 3 MV/cm). We have used these films to make metal-insulator-semiconductor (MIS) devices on n-type silicon wafers. C-V measurements accomplished on the structures indicate that the interface trap density is kept in the range (3 - 5) x 10(11) cm(-2) eV(-1) for films with the N/Si ratio below 1.38. For films where the N/Si ratio is higher than 1.3, the trap density suddenly increases, following the same trend of the concentration of N-H bonds in the SiNx:H films. The results are explained on the basis of the model recently reported by Lucovsky [J. Vac. Sci. Technol. B 14, 2832 (1996)] for the electrical behavior of (oxide-nitride-oxide)/Si structures. The model is additionally supported by deep level transient spectroscopy measurements, that show the presence of silicon dangling bonds at the insulator/semiconductor interface (the so-called P-bN0 center), The concentration of these centers follows the same trend with the film composition of the interface trap density and, as a consequence, with the concentration of N-H bonds. This result further supports the N-H bonds located at the insulator/semiconductor interface which act as a precursor site to the defect generation of the type . Si=Si-3, i.e., the P-bN0 centers. A close relation between interface trap density, P-bN0 centers and N-H bond density is established

Role of deep levels and interface states in the capacitance characteristics of all‐sputtered CuInSe2/CdS solar cell heterojunctions

All‐sputtered CuInSe2/CdS solar cellheterojunctions have been analyzed by means of capacitance‐frequency (C‐F) and capacitance‐bias voltage (C‐V) measurements. Depending on the CuInSe2 layer composition, two kinds of heterojunctions were analyzed: type 1 heterojunctions (based on stoichiometric or slightly In‐rich CuInSe2 layers) and type 2 heterojunctions (based on Cu‐rich CuInSe2 layers). In type 1 heterojunctions, a 80‐meV donor level has been found. Densities of interface states in the range 101 0–101 1 cm2 eV− 1 (type 1) and in the range 101 2–101 3 cm− 2 eV− 1 (type 2) have been deduced. On the other hand, doping concentrations of 1.6×101 6 cm− 3 for stoichiometric CuInSe2 (type 1 heterojunction) and 8×101 7 cm− 3 for the CdS (type 2 heterojunction) have been deduced from C‐Vmeasurements

Inversion charge study in TMO hole-selective contact-based solar cells

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this article, we study the effect of the inversion charge ( Q inv ) in a solar cell based on the hole-selective characteristic of substoichiometric molybdenum oxide (MoO x ) and vanadium oxide (VO x ) deposited directly on n-type silicon. We measure the capacitance–voltage ( C – V ) curves of the solar cells at different frequencies and explain the results taking into account the variation of the space charge and the existence of Q inv in the c-Si inverted region. The high-frequency capacitance measurements follow the Schottky metal–semiconductor theory, pointing to a low inversion charge influence in these measurements. However, for frequencies lower than 20 kHz, an increase in the capacitance is observed, which we relate to the contribution of the inversion charge. In addition, applying the metal–semiconductor theory to the high-frequency measurements, we have obtained the built-in voltage potential and show new evidence about the nature of the conduction process in this structure. This article provides a better understanding of the transition metal oxide/n-type crystalline silicon heterocontact.The authors would like to acknowledge the CAI de Técnicas Físicas of the Universidad Complutense de Madrid. The authors would also like to thank the Mexican grants program CONACyT for its financial collaboration.Peer ReviewedPostprint (author's final draft

Population-based analysis of POT1 variants in a cutaneous melanoma case–control cohort

Pathogenic germline variants in the protection of telomeres 1 gene (POT1) have been associated with predisposition to a range of tumour types, including melanoma, glioma, leukaemia and cardiac angiosarcoma. We sequenced all coding exons of the POT1 gene in 2928 European-descent melanoma cases and 3298 controls, identifying 43 protein-changing genetic variants. We performed POT1-telomere binding assays for all missense and stop-gained variants, finding nine variants that impair or disrupt protein–telomere complex formation, and we further define the role of variants in the regulation of telomere length and complex formation through molecular dynamics simulations. We determine that POT1 coding variants are a minor contributor to melanoma burden in the general population, with only about 0.5% of melanoma cases carrying germline pathogenic variants in this gene, but should be screened in individuals with a strong family history of melanoma and/or multiple malignancies

VERBAL FACE THREATENING ACTS USED BY RUBEUS HAGRID IN HARRY POTTER AND THE SORCERER’S STONE MOVIE

Language is one of the communication tools used by everyone in interacting with other people. Every word spoken by a language speaker has meaning and purpose, either directly or indirectly. Any expression that belongs to a face-threatening act, whatever it may be and goes against the wishes of the speaker's face, and any part of the speech is considered a face-threatening act. Pragmatics is a strategy to analyze what is the purpose of understanding speech, in pragmatics, there is politeness to knowing how people express negative and positive faces. When people talk to other people, they apply both positive and negative faces in communication to save threatening actions. In this study, Harry Potter and the Sorcerer's Stone analyzed face- threatening actions using the theory of Brown and Levison. In the study aims to determine the verbal face shape used by Rubeus Hagrid in the film. The research procedure is watching a movie or script on youtube, identifying and paying attention to the forms of actions that threaten their faces and classifying positive and negative politeness strategies. The results showed that there are 24 face-threatening actions from 3 forms of threatening actions (actions that threaten the listener's positive face, actions that threaten the listener's negative face, and actions that threaten the speaker's positive) and 4 threatening strategies1)Off –record, 2) Bald on record, 3) negative politeness, 4) positive politeness. For the response of his interlocutor, Rubeus Hagrid often responds to his interlocutor directly. Keywords: Face Threatening Acts, politeness Strategy, Harry potter movi