What Is a Magnetic Semiconductor?

Magnetic semiconductor (English: Magnetic semiconductor ) is a semiconductor material that combines both ferromagnetism (or similar effects) and semiconductor characteristics.

Magnetic semiconductor (English: Magnetic semiconductor ) is a semiconductor material that combines both ferromagnetism (or similar effects) and semiconductor characteristics. If magnetic semiconductors are used in the device, they will provide a new way of conducting electricity. Traditional electronic components work on the basis of controlling the degree of freedom of charge (thus n-type and p-type semiconductors). Magnetic semiconductors can control the spin degree of freedom of electrons (there are components of up and down rotation). It is possible to achieve spin polarization with a spin injection rate close to 100%. Theoretically, this will provide near-complete spin polarization (only up to 50% of polarization in materials such as iron), which is an important application of spin electronics, such as spin transistors. ^[1]

The history of magnetic semiconductor development can be divided into three sections.

At present, the research focus of magnetic semiconductors is mainly two types of semiconductors: dilute magnetic semiconductors and ferromagnetic semiconductors.

Magnetic semiconductor

Diluted magnetic semiconductors (DMS) refer to magnetic semiconductors formed by replacing some atoms in nonmagnetic semiconductors with transition metals (TM). Because the impurity concentration is generally not high and the magnetic properties are weak, it is called a dilute magnetic semiconductor or a semi-magnetic semiconductor. Because it has both semiconductor and magnetic properties, that is, the simultaneous application of two degrees of freedom of electronic charge and spin in a material, it has attracted widespread attention from researchers, and it is still in the research stage. Existing problems focus on the magnetic source of dilute magnetic semiconductors. If the research results are the same as people think, it will bring a new revolution to the computer field.

Diluted magnetic semiconductors have the properties of both semiconductors and magnetic materials, making it possible to simultaneously use the electronic charge and electronic spin in semiconductors, and provide the conditions for opening up new fields of semiconductor technology and preparing new electronic devices. Although the current research on the application of DMS materials is still in the experimental exploration stage, it has shown its broad application prospects. If the DMS material is used as an interface layer between a magnetic metal and a semiconductor, the injection of spin-polarized carriers into a non-magnetic semiconductor can be used to manufacture a spin-polarized light-emitting diode. For some heterogeneous layers of ferromagnetic / non-magnetic layers, such as GaMnAs / AlGaAs / GaMnAs, etc., by adjusting external parameters such as temperature and electric field, the carrier concentration in the semiconductor layer and the magnetic layer This kind of magnetic coupling can be applied to the manufacture of new superlattice devices of magnetron and light control. ^[1]

Ferromagnetic semiconductor

The following are several types of ferromagnetic semiconductors:

1. The Curie temperatures of manganese-doped indium arsenide and gallium arsenide (GaMnAs) are 50-100k and 100-200k, respectively.

2. Manganese-doped indium antimonide has ferromagnetism and a manganese concentration of less than 1% at room temperature.

3. Oxide semiconductor:

   1. Manganese-doped indium oxide is ferromagnetic at room temperature.

   2.Zinc oxide

   3.manganese-doped zinc oxide

   4. Zinc oxide doped with n-type cobalt

4. Titanium dioxide: Cobalt-doped titanium dioxide, which is ferromagnetic at room temperature and has a Curie temperature above 400K; Cr is doped into titanium dioxide, which is ferromagnetic at room temperature and has a Curie temperature above 400K.

5. Tin oxide: manganese-doped tin oxide with a Curie temperature above 340K; iron ions doped with tin oxide at a Curie temperature of about 340K; strontium doped with tin oxide is a dilute magnetic semiconductor that can be artificially applied to silicon A thin film grows on it.

6. Samarium oxide: The Curie temperature is about 69k. It can also be doubled by doping other elements.

7. Nitride-based semiconductors: Chromium is doped into aluminum nitride. ^[1]