Bandgap Tunability in Zn(Sn,Ge)N<sub>2</sub> Semiconductor Alloys

Narang, Prineha; Chen, Shiyou; Coronel, Naomi C.; Gul, Sheraz; Yano, Junko; Wang, Lin Wang; Lewis, Nathan S.; Atwater, Harry A.

doi:10.1002/adma.201304473

Cited by 80 publications

(78 citation statements)

References 32 publications

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“…Elements like Al, In, Ga, etc can serve as a donor in ZnO lattice and increase the wide band gap which will improve the electrical and optical properties of ZnO. Al-doped ZnO is very useful in fabrication of optoelectronics devices and detectors [15,16]. Ozgur et al has reported that the UV emission of un-doped ZnO NSs can be altered to blue emission by controlling the bandgap and oxidation states of Zn [17].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

et al. 2015

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Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn -), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo +) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs.

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Section: Introductionmentioning

confidence: 99%

Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

et al. 2015

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“…Absorption edges ranging from 2.0 to 3.1 eV have already been demonstrated in Zn(Ge,Sn) N 2 alloys. [ 6 ] Even wider spectral coverage from the infrared to the ultraviolet is predicted for Zn(Si,Sn)N 2 alloys. [ 7 ] However, an alternative to alloying for tuning the band gap of ZnSnN 2 was recently proposed.…”

Section: Doi: 101002/aenm201501462mentioning

confidence: 99%

Band Gap Dependence on Cation Disorder in ZnSnN₂ Solar Absorber

Veal

Feldberg

Quackenbush

et al. 2015

Advanced Energy Materials

103

112

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calculations revealed that altering the degree of cation disorder from none to maximal disorder using the special quasirandom structure (SQS) approach can change the fundamental band gap from 2.09 to 1.12 eV. The possibility of realizing such a variation experimentally was supported by the observation of the cation-disorder-induced wurtzite phase in molecular-beam epitaxy-grown thin fi lms as opposed to the theoretically more stable orthorhombic phase. [ 3 ] The cation-ordered orthorhombic structure is a superstructure of wurtzite structure, with similar tetrahedral bonding, as described in ref. [ 7 ] .Here, the observed absorption edges as a function of free electron density for the differently grown fi lms are consistent with the room temperature fundamental band gap varying from 1.0 to 2.0 eV as the cation ordering increases. Moreover, the conduction and valence band density of states (DOS) have been calculated using hybrid DFT for the cation-ordered orthorhombic and cation-disordered SQS pseudowurtzite phases. Comparison of these DOS with photoemission data from single crystal ZnSnN 2 fi lms grown under different conditions indicates that samples with different degrees of cation ordering have been synthesised, opening up a new method for tuning the band gap of ZnSnN 2 fi lms.The growth conditions for molecular-beam epitaxy (MBE) of the single crystal ZnSnN 2 thin fi lms are summarized in Table 1 . The substrate temperature, the Zn:Sn fl ux ratio and the N 2 pressure were adjusted to vary the degree of cation disorder in the ZnSnN 2 in order to experimentally test the theoretical predictions. X-ray diffraction indicates that all the samples have the wurtzite structure rather than the fully ordered orthorhombic structure (and also that Zn-nitride and Sn-nitride phases are below the detection limit); specifi cally, the peak at 22° which is characteristic of the orthorhombic structure is absent for all fi lms. [ 3 ] Thus, XRD characterization alone is insuffi cient to exclude the possibility of a signifi cant variation of the degree of cation disorder within the samples grown under the range of conditions employed. Consequently, evidence of cation disorder induced variations in the band gap and band structure has been sought and found in the optical, transport and photoemission properties of the ZnSnN 2 fi lms. It is important to note here that in the nonequilibrium growth technique used in this study (plasma-assisted MBE), substrate temperature and fl ux ratio have a profound infl uence on adatom migration length, and hence how atoms incorporate into an epitaxially driven structure. Therefore, higher growth temperature is likely to produce a more ordered fi lm than a lower growth temperature.

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“…Additionally, such II‐IV‐N 2 compounds show lattice parameters similar to those of (Al,Ga,In)N, which enable the formation of hybrid structures or epitaxial growth on group 13 nitrides. In the last few years, different studies examined the synthesis and properties of II‐IV‐N 2 compounds . However, the bulk synthesis of these materials is still challenging.…”

Section: Introductionmentioning

confidence: 99%

Solid Solutions of Grimm–Sommerfeld Analogous Nitride Semiconductors II‐IV‐N₂ (II=Mg, Mn, Zn; IV=Si, Ge): Ammonothermal Synthesis and DFT Calculations

Mallmann

Niklaus

Rackl

et al. 2019

Chemistry A European J

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Grimm–Sommerfeld analogous II‐IV‐N2 nitrides such as ZnSiN2, ZnGeN2, and MgGeN2 are promising semiconductor materials for substitution of commonly used (Al,Ga,In)N. Herein, the ammonothermal synthesis of solid solutions of II‐IV‐N2 compounds (II=Mg, Mn, Zn; IV=Si, Ge) having the general formula (IIa 1−xIIb x)‐IV‐N2 with x≈0.5 and ab initio DFT calculations of their electronic and optical properties are presented. The ammonothermal reactions were conducted in custom‐built, high‐temperature, high‐pressure autoclaves by using the corresponding elements as starting materials. NaNH2 and KNH2 act as ammonobasic mineralizers that increase the solubility of the reactants in supercritical ammonia. Temperatures between 870 and 1070 K and pressures up to 200 MPa were chosen as reaction conditions. All solid solutions crystallize in wurtzite‐type superstructures with space group Pna21 (no. 33), confirmed by powder XRD. The chemical compositions were analyzed by energy‐dispersive X‐ray spectroscopy. Diffuse reflectance spectroscopy was used for estimation of optical bandgaps of all compounds, which ranged from 2.6 to 3.5 eV (Ge compounds) and from 3.6 to 4.4 eV (Si compounds), and thus demonstrated bandgap tunability between the respective boundary phases. Experimental findings were corroborated by DFT calculations of the electronic structure of pseudorelaxed mixed‐occupancy structures by using the KKR+CPA approach.

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Bandgap Tunability in Zn(Sn,Ge)N₂ Semiconductor Alloys

Cited by 80 publications

References 32 publications

Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

Band Gap Dependence on Cation Disorder in ZnSnN₂ Solar Absorber

Solid Solutions of Grimm–Sommerfeld Analogous Nitride Semiconductors II‐IV‐N₂ (II=Mg, Mn, Zn; IV=Si, Ge): Ammonothermal Synthesis and DFT Calculations

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Bandgap Tunability in Zn(Sn,Ge)N2 Semiconductor Alloys

Cited by 80 publications

References 32 publications

Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

Band Gap Dependence on Cation Disorder in ZnSnN2 Solar Absorber

Solid Solutions of Grimm–Sommerfeld Analogous Nitride Semiconductors II‐IV‐N2 (II=Mg, Mn, Zn; IV=Si, Ge): Ammonothermal Synthesis and DFT Calculations

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Bandgap Tunability in Zn(Sn,Ge)N₂ Semiconductor Alloys

Band Gap Dependence on Cation Disorder in ZnSnN₂ Solar Absorber

Solid Solutions of Grimm–Sommerfeld Analogous Nitride Semiconductors II‐IV‐N₂ (II=Mg, Mn, Zn; IV=Si, Ge): Ammonothermal Synthesis and DFT Calculations