Very small crystals composed of 1000 to 100,000 atoms, called quantum dots, are being investigated for use in electronic devices. (a) A quantum dot was made of solid silicon in the shape of a sphere, with a diameter of 4 nm. Calculate the mass of the quantum dot, using the density of silicon (2.3 g/cm3). (b) How many silicon atoms are in the quantum dot? (c) The density of germanium is 5.325 g/cm3. If you made a 4-nm quantum dot of germanium, how many Ge atoms would it contain? Assume the dot is spherical.
Answer : Solution Step 1 of 5 Quantum dots (QD) are very small semiconductor particles, only several nanometres in size, so small that their optical and electronic properties differ from those of larger particles. They are a central theme in nanotechnology.