Solid–Solution Semiconductor Nanowires in Pseudobinary Systems

Liu, Baodan; Bando, Yoshio; Liu, Lizhao; Zhao, Jijun; Mitome, Masanori; Jiang, Xin; Golberg, Dmitri

doi:10.1021/nl303501t

Cited by 36 publications

(53 citation statements)

References 25 publications

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“…To examine the correlation between band gap and composition, other synthetic methods to make bulk (Ga 1Àx Zn x )(N 1Àx O x ) have been explored. [33][34][35][36] As described in our previous report, 32 single crystalline (Ga 1Àx Zn x )(N 1Àx O x ) nanoparticles with diameters of $18 nm and x ranging from 0.30 to 0.87 can be obtained by exposure of a mixture of ZnO and ZnGa 2 O 4 nanocrystals to NH 3 at 650 C. The x value here refers to the overall molar composition of the sample usually measured by elemental analysis of the metal content, i.e., x ¼ Zn/(Zn + Ga). The earliest reported methods included nanowires as well as $10 nm nanoparticles with a range of x values from 0.08 to 0.48.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of (Ga_1−xZn_x)(N_1−xO_x) nanocrystals with a wide range of compositions

Lee

Chuang

et al. 2016

J. Mater. Chem. A

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We describe the synthesis and characterization of wurtzite (Ga 1Àx Zn x )(N 1Àx O x ) nanocrystals with a wide range of compositions and a focus on properties relevant for solar fuel generation. (Ga 1Àx Zn x )(N 1Àx O x ), a solid solution of GaN and ZnO, is an intriguing material because it exhibits composition-dependent visible absorption even though the parent semiconductors absorb in the UV. When functionalized with co-catalysts, (Ga 1Àx Zn x )(N 1Àx O x ) is also capable of water splitting under visible irradiation. Here, we examine the synthesis of (Ga 1Àx Zn x )(N 1Àx O x ) nanocrystals to understand how they form by nitridation of ZnO and ZnGa 2 O 4 nanocrystalline precursors. We find that the ZnO precursor is critical for the formation of crystalline (Ga 1Àx Zn x )(N 1Àx O x ) at 650 C, consistent with a mechanism in which wurtzitenucleates topotactically on wurtzite ZnO at an interface with ZnGa 2 O 4 . Using this information, we expand the range of compositions from previously reported 0.30 # x # 0.87 to include the low-x and high-x ends of the range. The resulting compositions, 0.06 # x # 0.98, constitute the widest range of (Ga 1Àx Zn x )(N 1Àx O x ) compositions obtained by one synthetic method. We then examine how the band gap depends on sample composition and find a minimum of 2.25 eV at x ¼ 0.87, corresponding to a maximum possible solar-to-H 2 power conversion efficiency of 12%. Finally, we examine the photoelectrochemical (PEC) oxidation behavior of thick films of (Ga 1Àx Zn x )(N 1Àx O x ) nanocrystals with x ¼ 0.40, 0.52, and 0.87 under visible illumination. (Ga 1Àx Zn x )(N 1Àx O x ) nanocrystals with x ¼ 0.40 exhibit solar PEC oxidation activity that, while too low for practical applications, is higher than that of bulk (Ga 1Àx Zn x )(N 1Àx O x ) of the same composition. The highest photocurrents are observed at x ¼ 0.52, even though x ¼ 0.87 absorbs more visible light, illustrating that the observed photocurrents are a result of an interplay of multiple parameters which remain to be elucidated. This set of characterizations provides information useful for future studies of composition-dependent PEC properties of nanoscale (Ga 1Àx Zn x )(N 1Àx O x ). † Electronic supplementary information (ESI) available: Fitting of XRD patterns in Fig. 2; TEM images of the samples from Fig. 2; XRD patterns, elemental analysis by ICP-OES, and diffuse reectance spectra of the products from nitridation of the starting mixture with x ¼ 0.78 with varying nitridation time; TEM images of the nitrided products of x ¼ 0.06, 0.24, 0.91, and 0.98; XPS spectra of Zn2p 3/2 , O1s, Ga2p 3/2 , and N1s in samples with several compositions; determination of band gap as a function of composition. See

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Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of (Ga_1−xZn_x)(N_1−xO_x) nanocrystals with a wide range of compositions

Lee

Chuang

et al. 2016

J. Mater. Chem. A

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“…For intrinsic semiconductors, the optical and electrical properties such as conductivity type, carrier density, and mobility, as well as the band structure, are usually confined subjected to their own nature . The electrical conductivity of semiconductors shows a strong impact on the integration of photoelectricity and electrical devices . Good examples in this context are field effect transistor and light emitting diode (LED).…”

Section: Introductionmentioning

confidence: 99%

“…Unfortunately, this replacement occurs randomly and often incompletely. The growth conditions of a homogeneous crystallization of such solid‐solutions are strictly confined to a local equilibrium . Even slight deviations in composition or temperature will result in a phase separation or might cause the formation of core–shell structures .…”

Section: Introductionmentioning

confidence: 99%

Pseudobinary Solid‐Solution: An Alternative Way for the Bandgap Engineering of Semiconductor Nanowires in the Case of GaP–ZnSe

Yang

Liu

Yang

et al. 2015

Adv Funct Materials

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Bandgap engineering of semiconductor nanostructures is of significant importance either for the optical property tailoring or for the integration of functional optoelectronic devices. Here, an efficient way to control the bandgap and emission wavelength is reported for a binary compound semiconductor through alloying with another binary compound. Taking GaP‐ZnSe system as an example, the bandgap of quaternary GaP‐ZnSe solid‐solution nanowires can be selectively tailored in the range of 1.95–2.2 eV by controlling the solubility of ZnSe dopants in GaP host. High‐resolution transmission electron microscopy measurement and chemical analyses using an X‐ray energy dispersive spectrometer (EDS) demonstrate the solid‐solution feature of GaP‐ZnSe semiconductor alloy, while X‐ray photoelectron spectroscopy (XPS) characterization verifies the formation of some new chemical bonds corresponding to Zn‐P and Ga‐S bonds in GaP‐ZnSe nanowires. The strategy to tailor the optoelectronic property of semiconductor nanostructures through the solid‐solution of two different binary compounds represents a general routine to the property modification of all pseudobinary systems and will open more opportunity for their applications in electronics, optics and optoelectronics.

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“…Recently, Liu et al reported the synthesis of (GaP) 1−x (ZnS) x NWs at a composition x = 0.045 and 0.968. 32 The Pan group have reported (GaAs) 1−x (ZnSe) x NWs with compositions in the range of x < 0.5. 33…”

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confidence: 99%

GaP–ZnS Pseudobinary Alloy Nanowires

Park

Lee

et al. 2014

Nano Lett.

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Multicomponent nanowires (NWs) are of great interest for integrated nanoscale optoelectronic devices owing to their widely tunable band gaps. In this study, we synthesize a series of (GaP)(1-x)(ZnS)(x) (0 ≤ x ≤ 1) pseudobinary alloy NWs using the vapor transport method. Compositional tuning results in the phase evolution from the zinc blende (ZB) (x < 0.4) to the wurtzite (WZ) phase (x > 0.7). A coexistence of ZB and WZ phases (x = 0.4-0.7) is also observed. In the intermediate phase coexistence range, a core-shell structure is produced with a composition of x = 0.4 and 0.7 for the core and shell, respectively. The band gap (2.4-3.7 eV) increases nonlinearly with increasing x, showing a significant bowing phenomenon. The phase evolution leads to enhanced photoluminescence emission. Strikingly, the photoluminescence spectrum shows a blue-shift (70 meV for x = 0.9) with increasing excitation power, and a wavelength-dependent decay time. Based on the photoluminescence data, we propose a type-II pseudobinary heterojunction band structure for the single-crystalline WZ phase ZnS-rich NWs. The slight incorporation of GaP into the ZnS induces a higher photocurrent and excellent photocurrent stability, which opens up a new strategy for enhancing the performance of photodetectors.

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Solid–Solution Semiconductor Nanowires in Pseudobinary Systems

Cited by 36 publications

References 25 publications

Synthesis and characterization of (Ga_1−xZn_x)(N_1−xO_x) nanocrystals with a wide range of compositions

Synthesis and characterization of (Ga_1−xZn_x)(N_1−xO_x) nanocrystals with a wide range of compositions

Pseudobinary Solid‐Solution: An Alternative Way for the Bandgap Engineering of Semiconductor Nanowires in the Case of GaP–ZnSe

GaP–ZnS Pseudobinary Alloy Nanowires

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Solid–Solution Semiconductor Nanowires in Pseudobinary Systems

Cited by 36 publications

References 25 publications

Synthesis and characterization of (Ga1−xZnx)(N1−xOx) nanocrystals with a wide range of compositions

Synthesis and characterization of (Ga1−xZnx)(N1−xOx) nanocrystals with a wide range of compositions

Pseudobinary Solid‐Solution: An Alternative Way for the Bandgap Engineering of Semiconductor Nanowires in the Case of GaP–ZnSe

GaP–ZnS Pseudobinary Alloy Nanowires

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Product

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Synthesis and characterization of (Ga_1−xZn_x)(N_1−xO_x) nanocrystals with a wide range of compositions

Synthesis and characterization of (Ga_1−xZn_x)(N_1−xO_x) nanocrystals with a wide range of compositions