A structure zone diagram obtained by simultaneous deposition on a novel step heater: A case study for Cu₂O thin films

Abstract

In thin film deposition processes, the deposition temperature is one of the crucial process parameters for obtaining films with desired properties. Usually the optimum deposition temperature is found by conducting several depositions sequentially in a time consuming process. This paper demonstrates a facile and rapid route of the simultaneous thin film deposition at six different deposition temperatures ranging from 100 to 1000 8C. Cuprite (Cu 2 O) was chosen for the study as this material is of interest for energy applications. The thin films are assessed for their crystallographic, microstructural, Raman scattering, and photoelectrochemical properties. The results show that the utilization of a step heater leads to the rapid optimization of thin film microstructures of an absorber material used in photoelectrochemistry. This results in a structure zone diagram for Cu 2 O. For a substrate temperature of 600 8C, an optimum between crystallinity and morphology occurs. 1 Introduction Thin film semiconductors in photoelectrochemical applications need to fulfil numerous properties. Whereas the search for new absorber and catalytic materials by combinatorial and high-throughput methods is currently addressed, the high-throughput optimization of deposition parameters, e.g., deposition temperature, however, is less developed. Finding optimal deposition conditions for even relatively simple metal oxide semiconductors for photoelectrochemical applications [1], usually requires careful evaluation of the different properties of a thin film like morphology, crystal structure, and interface formation [2][3][4][5]. In reactive magnetron sputtering, these properties can be tuned by deposition parameters like applied power, gas flow, substrate rotation, deposition geometry, total or partial gas pressure, and substrate temperature. These parameters are, however, interdependent. Attaining the desired metal oxide phase (e.g., competing phase formation between CuO and Cu 2 O) adds to the overall complexity of the problem of finding optimal deposition parameters [6]. Evaluating all possible optimization

Raman spectroscopy characterization of 10‐cash productions from the late Chinese emperors to the Republic

“…The spectrum of cuprite shows two main bands at 114 and 220 cm −1 , accompanied by shoulders at 145 and 186 cm −1 , which are in agreement with literature data . Weak, broad bands also appear at 420, 525, and 625 cm −1 . These last bands can be assigned to Cu 2 O amorphous or finely divided, and characterize defective cuprite forming native passive layer on copper/bronze objects .…”

“…These last bands can be assigned to Cu 2 O amorphous or finely divided, and characterize defective cuprite forming native passive layer on copper/bronze objects . The spectrum of tenorite was dominated by the band at 297 cm −1 , accompanied by weak signals at 346 and 631 cm −1 , also in agreement with literature …”

“…For this purpose, it was hypothesized that, when series of objects experiencing a common corrosion conditions was studied, even subtle differences in the composition and/or metallographic structure of the base metal will be reflected in the composition of the corrosion layers and the distribution of the corrosion products through the patina, which can be detected by means of Raman spectroscopy. This idea, which is in agreement with previous studies on bronze coins using solid‐state electrochemical techniques, is consistent with the reported sensitivity of the Raman spectra of copper oxides, cuprite in particular, to the crystallinity and grain size, in particular, in thin solid films . It has to be noted, however, that the “corrosion history” experienced by the objects under study may have been considerably different so that the above hypothesis can only be reasonably applied to selected sets of samples.…”

Influence of Substrate Temperature and Film Thickness on Thermal, Electrical, and Structural Properties of HPPMS and DC Magnetron Sputtered Ge Thin Films

“…For a simultaneous deposition at different T S , a special step heater was used: Ge films were deposited simultaneously on five substrates held at five different temperatures between 200 and 800 °C with steps of 150 °C. In addition, a single Ge film was deposited at room temperature by DC sputtering, using the same parameters as mentioned before, and subsequently annealed at 500 °C for 2 h.…”

Predicting structure zone diagrams for thin film synthesis by generative machine learning

“…Although SZD are useful and popular, they only have a very limited predictive capability since they are based on many generalizations and assumptions, e.g., the pressure is a proxy for the constitution of the incoming particle flux (kinetic energy, ratio of ion-to-growth flux, flux composition). Several revised SZD have in common that they are either strongly abstracted 27 or materials specific 28 . Classical SZD relate processing to microstructure, however only for single elements or binary systems and using system-specific deposition process parameters like gas pressure or substrate bias, which are almost impossible to transfer between deposition systems.…”