is given by the de Broglie relation , where h is the Planck constant and p is the electron momentum. For example, a 1 kilo-electron volt (keV) electron has a wavelength of slightly less than 0.04 nm. A 5 eV electron has a wavelength of 0.55 nm. This yields X-ray-like resolution without depositing significant energy. In order to ensure against charging, it must be ensured that electrons can penetrate sufficiently to reach the conducting substrate. A fundamental concern for using low-energy electrons (≪100 eV) with this technique is their natural tendency to repel one another due to Coulomb forces as well as Fermi–Dirac statistics, though electron anti-bunching has been verified only in a single case. Atom holographic lithography The interference of atomic de Broglie waves is also possible provided one can obtain coherent beams of cooled atoms. The momentum of an atom is even larger than for electrons or photons, allowing even smaller wavelengths, per the de Broglie relation. Generally the wavelength will be smaller than the diameter of the atom itself. Uses The benefit of using interference lithography is the quick generation of dense features over a wide area without loss of focus. Seamless diffraction gratings on areas of more than one square meter have been originated by interference lithography. Hence, it is commonly used for the origination of master structures for subsequent micro or nano replication processes (e.g. nanoimprint lithography) or for testing photoresist processes for lithography techniques based on new wavelengths (e.g., EUV or 193 nm immersion). In addition, interfering laser beams of high-power pulsed lasers provides the opportunity of applying a direct treatment of the material's surface (including metals, ceramics and polymers) based on photothermal and/or photochemical mechanisms. Due to the above-mentioned characteristics, this method has been called in this case "Direct Laser Interference Patterning" (DLIP). Using DLIP, the substrates can be structured directly in one-step obtaining a periodic array on large areas in a few seconds. Such patterned surfaces can be used for different applications including tribology (wear and friction reduction), photovoltaics (increased photocurrent), or biotechnology. Electron interference lithography may be used for patterns which normally take too long for conventional electron beam lithography to generate. The drawback of interference lithography is that it is limited to patterning arrayed features or uniformly distributed aperiodic patterns only. Hence, for drawing arbitrarily shaped patterns, other photolithography techniques are required. In addition, for electron interference lithography non-optical effects,