Herbert Kroemer

Asteroid 24751, discovered on 21 September 1992 has been named as Asteroid Kroemer in his honor.

Herbert Kroemer was born on August 25, 1928, in Weimar, which after the Second World War became a part of German Democratic Republic (East Germany). None of his parents attended high school. His father worked for city administration and his mother was a typical German homemaker.

Herbert is the eldest of his parent’s three children. Though little educated, his parents were determined to give their children the best education. His mother was especially keen on it and relentlessly pushed him to score the highest mark in class.

He was a brilliant student, especially fond of physics, chemistry and mathematics. However, just like many other brilliant students, young Herbert frequently felt very bored and entertained himself by disturbing his classmates. It was his academic excellence, which prevented him from being expelled.

In 1947, he passed out from gymnasium and entered the University of Jena with physics. Unfortunately, by the following year, the University came under state scrutiny and students began to disappear; some escaped to West Germany, others were arrested and sent to work in mines.

In 1948, Kroemer moved to Berlin as a summer student at the Siemens Company. As the ‘Berlin airlift’ began he decided to move to West Germany via one of the empty airlift return flights. Before going over, he wrote to several West German universities for admission, but did not receive any reply.

Soon after receiving his PhD in 1952, Herbert Kroemer began his career as a ‘House Theorists’ at the Central Telecommunications Laboratory (FTZ) of the German postal service. His duty was to answer any theoretical question that any group member might have and give weekly talk on any appropriate subject.

Later, he began working on the frequency limitations of the new transistors, which led to his work on heterostructures. In 1954, he wrote a paper outlining his first ideas about the heterostructure bipolar transistor.

Later in the same year, he shifted to the United States of America and joined the RCA Laboratories in Princeton, New Jersey as research scientist. Here he resumed his work on heterostructures and published two important papers.

In one of them, published in 1957, he spelled out the concept of quasielectric fields, which he considered to be the fundamental design principle for all heterostructures. Unfortunately, it attracted little attraction.

Soon he began to feel homesick and in 1957 went back to Germany. There he joined Philips Semiconductor Research Group in Hamburg as the Group Leader. However, he was not fully satisfied with the work.

Herbert Kroemer is best known for his work on heterostructure bipolar transistors (HBP). In 1957, he published a paper, in which he described his idea of quasielectric fields, which turned out to be the fundamental design for all heterostructures.

Later in 1963, he carried out the calculation and theoretically showed that heterostructure transistor would be superior to a conventional transistor, especially for certain high-frequency uses. This is because unlike most computer chips and semiconductor components heterostructures are made of different materials.