Zero Thermal Expansion in a Nanostructured Inorganic-Organic Hybrid Crystal

There are very few materials that exhibit zero thermal expansion (ZTE), and of these even fewer are appropriate for electronic and optoelectronic applications. We find that a multifunctional crystalline hybrid inorganic-organic semiconductor, β-ZnTe(en)_0.5 (en denotes ethylenediamine), shows uniaxial ZTE in a very broad temperature range of 4–400 K, and concurrently possesses superior electronic and optical properties. The ZTE behavior is a result of compensation of contraction and expansion of different segments along the inorganic-organic stacking axis. This work suggests an alternative route to designing materials in a nanoscopic scale with ZTE or any desired positive or negative thermal expansion (PTE or NTE), which is supported by preliminary data for ZnTe(pda)_0.5 (pda denotes 1,3-propanediamine) with a larger molecule.