Before talking more about specific inventions, I want to introduce the fundamental science that made them possible.
When physicists such as Planck, Bohr, de Broglie, Heisenberg, Schrödinger, Dirac, and Einstein formulated quantum mechanics from 1900 to 1930, they were trying to understand the fundamental laws of the universe, not invent something of great economic importance. But it turns out they did, as we shall explain below. And when the great physicist Paul Dirac said in 1929 that all of chemistry could, in principle, be explained in terms of the newly formulated theory of quantum mechanics, probably few people believed him. But it turns out he was right. As far as we know, the structure of every atom in the universe is determined by quantum mechanics. Today, all chemists and material scientists are trained extensively in quantum mechanics, as evidenced by this chemistry class at Harvard. Biologists like Francis Crick, who won the 1962 Nobel Prize in Medicine for the discovery of DNA, realized many years ago that even biology is ultimately governed by the laws of physics and quantum mechanics.
A thorough understanding of quantum mechanics is necessary to engineer solid state devices such as transistors. Transistors are the building blocks of electronics and computers. It is impossible to understanding semiconductors (the building blocks of transistors), or any material for that matter, with classical physics alone (i.e. physics known before the discoveries of quantum mechanics and relativity). The physics of lasers and the interaction of light with matter are described by what's called quantum electrodynamics. Even the light entering your eye from this computer screen requires quantum mechanics to understand! Elementary particle physics describes the fundamental building blocks of the universe in the language of relativistic quantum field theory, which is basically quantum mechanics mixed with Einstein's relativity. Without quantum mechanics, the "information age" (and much of modern science) would not exist today.
This discovery of the electron by physicist J.J. Thompson in 1897 was probably underappreciated when it occurred, just like the development of quantum mechanics. After all, in 1897 it probably sounded like a waste of money to do experiments on a particle that is too tiny to ever see. But of course, now our civilization is dependent on electronics, chemistry, materials science, medicine, etc.--all of which require an understanding of the electron.
It is difficult to put a price tag on the amount of current U.S. gross domestic product that would not exist without the discoveries of the electron and quantum mechanics. But it would likely reach into the trillions of dollars. The inventions of the computer, the transistor, and the World Wide Web are also at the root of billions or trillions of dollars of our economy. The laser is used in fiber optics, which are the basis for a global telecommunications industry worth over a trillion dollars.
The 1906 Nobel Prize in Physics was given to J.J. Thomson for the discovery of the electron. The 1932 and 1933 Nobel Prizes were awarded to Heisenberg, Schrödinger, and Dirac for the development of quantum mechanics.
