n-type silicon

Silicon that has been doped with phosphorus gas to turn it into a material that contains extra electrons that it will release easily. P-type silicon is doped with boron gas to turn it into a material that contains holes that accept a free electron easily. Although "n" and "p" imply negative and positive, n-type and p-type silicon are in an "in-between" stage that has the inclination to readily become more negative and positive. See MOSFET.