An STM and LEED study of MOCVD-prepared P/Ge (1 0 0) to (1 1 1) surfaces

McMahon, William E.; Kibbler, A.; Olson, J. M.

doi:10.1016/j.susc.2004.08.008

Cited by 17 publications

(22 citation statements)

References 27 publications

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“…2b) we observe a (1 x 1) LEED pattern with a high background, which indicates a disordered surface. According to the literature, the P-terminated Ge(100) surface with 2° offcut shows a (9 x 2) surface reconstruction [10]. Since our XPS analysis confirms the presence of C and more than one ML of P on the Ge surface, we assume that the high background in the LEED pattern is related to the presence of excess of P and TBP by-products on the surface.…”

Section: Resultssupporting

confidence: 72%

“…In general, differences in the atomic order of probed (100) surfaces -such as cleanliness, surface reconstruction and chemical configuration-affect shape and amplitude of RA spectra [26]. Considering that (1) P induces changes on the surface reconstruction [10]; (2) the thickness estimation for the P coverage from XPS measurements is more than 1 MLof P; and (3) carbon [20] and TBP fragments [25] mainly reduce the observed signal intensity, we believe that the RA spectrum of Fig. 1 might arise from the surface reconstruction of the P terminated Ge(100) surface underneath a layer of TBP fragments.…”

Section: Resultsmentioning

confidence: 99%

“…Particularly, P termination of the Ge surface should be obtained prior to nucleation for state-of-the-art GalnP on Ge heteroepitaxy in MOVPE [10,11]. Phosphine (PH 3 ) and tertiarybutylphosphine (TBP) are nowadays the two main P precursors used in MOVPE systems.…”

Section: Introductionmentioning

confidence: 99%

“…Ge surfaces annealed under PH 3 feature P saturation to about one atomic layer at 573-720 K in low pressure CVD systems [12]. Low energy electron diffraction (LEED) analysis of a P-terminated Ge(100) surface with 2° offcut prepared by PH 3 exposure in MOVPE ambient shows a (9 x 2) surface reconstruction [10]. In contrast to AsH 3 , PH 3 does not etch the Ge surface [13].…”

Section: Introductionmentioning

confidence: 99%

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In situ study of Ge(100) surfaces with tertiarybutylphosphine supply in vapor phase epitaxy ambient

Barrigón¹,

Brückner²,

Supplie³

et al. 2013

Journal of Crystal Growth

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GalnP nucleation on Ge(100) often starts by annealing of the Ge(100) substrates under supply of phosphorus precursors. However, the influence on the Ge surface is not well understood. Here, we studied vicinal Ge(100) surfaces annealed under tertiarybutylphosphine (TBP) supply in MOVPE by in situ reflection anisotropy spectroscopy (RAS), X-ray photoelectron spectroscopy (XPS), and low energy electron diffraction (LEED). While XPS reveals a P termination and the presence of carbon on the Ge surface, LEED patterns indicate a disordered surface probably due to by-products of the TBP pyrolysis. However, the TBP annealed Ge(100) surface exhibits a characteristic RA spectrum, which is related to the P termination. RAS allows us to in situ control phosphorus desorption dependent on temperature.

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Section: Resultssupporting

confidence: 72%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

In situ study of Ge(100) surfaces with tertiarybutylphosphine supply in vapor phase epitaxy ambient

Barrigón¹,

Brückner²,

Supplie³

et al. 2013

Journal of Crystal Growth

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“…Additionally, the hydride annealing helps to further decrease some carbon contamination that might have survived the hightemperature bake. Several works are available in the literature detailing the features of group-V passivated Ge surfaces, resulting from hydride annealings in a MOVPE growth environment, both for the case of AsH 3 [9,16,17] and also of PH 3 surfaces [17,18]. On the one hand, AsH 3 has been reported to etch germanium significantly [9,16,17], even for temperatures of 540 1C [9] far below the typical ranges used in heteroepitaxy (600-650 1C).…”

Section: 3mentioning

confidence: 99%

Analysis of germanium epiready wafers for III–V heteroepitaxy

Rey‐Stolle

Barrigón

Galiana

et al. 2008

Journal of Crystal Growth

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Keywords:Al. Substrates Al. Surface processes A3. Metalorganic vapor-phase epitaxy B2. Semiconducting germanium Frequently, when growing III-V semiconductors on germanium substrates, unexpected differences between nominally identical substrates are encountered. Using atomic force microscopy (AFM), we have analysed a set of germanium substrates sharing the same specifications. The substrates come from the same vendor but different results come about in terms of the morphology of the epilayers produced by the same epitaxial routine (i.e. substrate W\ produced epilayers with good morphology while substrate WX produced epilayers with defects). The morphological analysis has been carried out on (a) epiready substrates; (b) samples after a high-temperature bake at 700 °C; and (c) on the samples after a hydride (PH 3 ) annealing at 640 °C. In the two first stages all substrates (both W\ and WX) show the same good morphology with RMS roughness below 3 A in all cases. It is in the third stage (annealing in PH 3 ) that the morphology degrades and the differences between the samples become apparent. After phosphine exposure at 640 °C, the RMS roughness of both substrates approximately doubles, and their surface appears as full of peaks and valleys on the nanometre scale. Despite the general appearance of the samples being similar, a careful analysis of their surface reveals that the substrates that produce bad morphologies (WX) show higher peaks, and some of their roughness parameters, namely, surface kurtosis and the surface skewness, are considerably degraded.

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In Situ Characterization of Interfaces Relevant for Efficient Photoinduced Reactions

Supplie

May

Brückner

et al. 2017

Adv Materials Inter

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which he pioneered and established. In general, interfaces do not only determine electronic properties of the final device; their atomic order also highly affects growth kinetics and defect formation. Moreover, the design of solid-liquid and hybrid interfaces determines their chemical reactivity and stability. In situ monitoring of interface preparation, formation, and interfacial reactions thus promises efficient process control. Paired with a detailed understanding of interface formation mechanisms, however, the true power of in situ control is to allow for specific modification and tuning of interface formation for the device of choice. There are several excellent reviews on in situ approaches covering wide ranges of materials from basic science to applications as well as varieties of preparation and analysis techniques. [2][3][4][5][6][7][8][9][10][11] As indicated in Figure 1, this review will be focused on in situ control over interfaces of materials that are relevant for photoinduced reactions in high-efficiency solar energy conversion and sensing applications with in situ control of semiconductor/polymer/ biological interfaces. We will restrict the techniques to realistic and complex, non-ultrahigh-vacuum (UHV) ambient, where in situ control is most demandingbut also highly desired. The more complex the interfacial reactions are, the more important is the in situ characterization. Ex situ approaches can contribute to an indirect understanding of interface formation, but to understand and, finally, control the dynamic processes taking place, real-time measurements are appropriate. The challenge, we are facing, is twofold: On the one hand, increased interaction with the surrounding ambient causes higher complexity. Yet at the same time, it decreases the number of applicable techniques. On the other hand, those techniques are often elaborate and not necessarily easy to interpret. In a nutshell, we will discuss four main topics:(i) Surface preparation during growth of structures for highefficiency solar energy conversion: World-record conversion efficiencies in both photovoltaics [12,13] and solar water splitting [14] are achieved with multijunction solar cells based on epitaxial III/V compound semiconductor structures. We will discuss in situ controlled preparation Solar energy conversion and photoinduced bioactive sensors are representing topical scientific fields, where interfaces play a decisive role for efficient applications. The key to specifically tune these interfaces is a precise knowledge of interfacial structures and their formation on the microscopic, preferably atomic scale. Gaining thorough insight into interfacial reactions, however, is particularly challenging in relevant complex chemical environment. This review introduces a spectrum of material systems with corresponding interfaces significant for efficient applications in energy conversion and sensor technologies. It highlights appropriate analysis techniques capable of monitoring critical physicochemical reactions in situ during non-vacuu...

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An STM and LEED study of MOCVD-prepared P/Ge (1 0 0) to (1 1 1) surfaces

Cited by 17 publications

References 27 publications

In situ study of Ge(100) surfaces with tertiarybutylphosphine supply in vapor phase epitaxy ambient

In situ study of Ge(100) surfaces with tertiarybutylphosphine supply in vapor phase epitaxy ambient

Analysis of germanium epiready wafers for III–V heteroepitaxy

In Situ Characterization of Interfaces Relevant for Efficient Photoinduced Reactions

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