Thin Film Synthesis of Semiconductors in the Mg–Sb–N Materials System

Abstract

Nitrides feature many interesting properties, such as a wide range of bandgaps suitable for optoelectronic devices including light-emitting diodes (LEDs), and piezoelectric response used in microelectromechanical systems (MEMS). Nitrides are also significantly underexplored compared to oxides and other chemistries, with many being thermochemically metastable, sparking interest from a basic science point of view. This paper reports on experimental and computational exploration of the Mg-Sb-N material system, featuring both metastable materials and interesting semiconducting properties. Using sputter deposition, we discovered a new Mg2SbN3 nitride with a wurtzite-derived crystal structure and synthesized the antimonide-nitride Mg3SbN with an antiperovskite crystal structure for the first time in thin film form. Theoretical calculations indicate that Mg2SbN3 is metastable and has properties relevant to LEDs and MEMS, whereas Mg3SbN has a large dielectric constant (28e0) and low hole effective masses (0.9m0), of interest for photovoltaic solar cell absorbers. The experimental solar-matched 1.3 eV optical absorption onset of the Mg3SbN antiperovskite agrees with the theoretical prediction (1.3 eV direct, 1.1 eV indirect), and with the measurements of room-temperature near-bandgap photoluminescence. These results make an important contribution towards understanding semiconductor properties and chemical trends in the Mg-Sb-N materials system, paving the way to future practical applications of these novel materials.

Wurtzite materials in alloys of rock salt compounds

“…It is also noteworthy that the effective mass of electrons in the WZ structure (0.3m 0 at x 5 0.2) with a direct band gap is much lower than that of electrons in the RS structure (1.5m 0 at x 5 0.2) with an indirect band gap, suggesting potential optoelectronic applications of WZ alloys if they could be doped n-type. Such differences in effective masses between tetrahedrally coordinated (WZ and ZB) and octahedrally coordinated (RS and NC) polymorphs have been reported in other binary chalcogenides [8,14] and in ternary nitrides [29,30,31].…”

Structure–Composition–Property Relationships in Antiperovskite Nitrides: Guiding a Rational Alloy Design

“…33 The value of Mg3NSb is in line with previous report. 17 Further, we decompose the static macroscopic dielectric tensor to ionic (ɛion) and electronic (ɛele) contributions separately, and focus on the ɛele, which is related with the electronic properties directly. A positive linear relationship between ɛele and t is clearly observed for Mg3NA (A 3-= P, As, Sb, Bi).…”

“…In addition to conventional perovskites ABX3, some researchers began to pay attention to their counterparts, antiperovskites (X3BA), [15][16][17][18] in which the B anions are located in the center of 6-fold coordinated octahedra and the A anions are 12-fold coordinated with the X cations (Figure 1). Recently, Gebhardt et al proposed a series of inverse-hybrid perovskites (CH3NH3)3BA (B: monovalent anions, A: divalent anions or B: divalent anions, A: monovalent anions).…”

“…15,19 On the contrary, several reported all-inorganic antiperovskite semiconductors X3NA (X 2+ = Ca 2+ , Mg 2+ ; A 3-= P 3-, Sb 3-, Bi 3-) possess suitable direct band gaps and high optical absorption coefficients, indicating that they are promising photovoltaic absorbers. 17,18,20 Exploring the composition-property relationships are very important for understanding and designing photovoltaic materials with excellent performance. 21 For conventional ABX3 perovskites, it is well known that the B-and X-site anions have major impacts on the electronic structures, while A-site cation does not contribute the band edge because of its highly ionic nature.…”

Influence of Protection Layers on Thermal Stability of Nitride Thin Films

“…In recent years, thin-film synthesis methods, guided by computational predictions of stability and structure, have also been used to synthesize previously unreported nitride materials with useful properties. [8,9] Among them are SnN [10] and Mg 2 SbN 3 [11] metastable with respect to nitrogen evolution, and Na 3 N [12] and ZnMoN 2 [13] metastable with respect to lower-energy polymorphs, both according to theoretical calculations. Experimentally, it is more challenging to evaluate thermodynamic stability of these new nitrides, or to understand the origin of their metastability in first place.…”