Question

Classify each of the following materials as metal, semiconductor, or insulator: (a) GaN (b) B (c) \(\mathrm{ZnO}\) (d) \(\mathrm{Pb}\)

Short answer

In conclusion, the classification of the given materials is: (a) GaN - Semiconductor (b) B - Semiconductor (c) ZnO - Semiconductor (d) Pb - Metal

Step-by-step solution

Identify the electrical conductivity and chemical properties of GaN

GaN stands for Gallium Nitride, which is a compound consisting of one Gallium (Ga) atom and one Nitrogen (N) atom. GaN is a wide bandgap semiconductor material with a high thermal conductivity and chemical stability.

Classify GaN

Based on its properties, GaN can be classified as a semiconductor.

Identify the electrical conductivity and chemical properties of B

B stands for Boron, which is an element found in group 13 (III A) of the periodic table. Pure boron is a poor conductor of electricity, but its conductivity can be increased through a process called doping.

Classify B

Based on its properties, B can be classified as a semiconductor.

Identify the electrical conductivity and chemical properties of ZnO

ZnO stands for Zinc Oxide, which is an inorganic compound consisting of one Zinc (Zn) atom and one Oxygen (O) atom. ZnO is widely used in the electronics industry due to its unique combination of electrical, optical, and piezoelectric properties.

Classify ZnO

Based on its properties, ZnO can be classified as a semiconductor.

Identify the electrical conductivity and chemical properties of Pb

Pb stands for Lead, which is an element found in group 14 (IV A) of the periodic table. It is a heavy metal with high electrical conductivity, malleability, and ductility.

Classify Pb

Based on its properties, Pb can be classified as a metal. In conclusion, the materials can be classified as follows: (a) GaN - Semiconductor (b) B - Semiconductor (c) ZnO - Semiconductor (d) Pb - Metal

Key concepts

Semiconductors

When we delve into the world of chemistry and physics, we encounter materials with unique properties that define the way we use them in technology. Semiconductors are such materials that have a conductivity level between that of an insulator and a metal. What does this mean? Simply put, semiconductors don't conduct electricity as well as metals but do a better job at it than insulators.

Materials like Gallium Nitride (GaN), Boron (B), and Zinc Oxide (ZnO) are examples of semiconductors. Typically, they are not very conductive in their pure form, but that changes when we introduce impurities in a process known as doping. Doping alters the electrical qualities of semiconductors, allowing us to fabricate devices like transistors, solar cells, and diodes—fundamental components in digital electronics and photovoltaics.

To understand semiconductors better, we look at the electron band structure. Semiconductors have a band gap that is small enough to allow for the electron jump from the valence to the conduction band with the help of heat or light, explaining how we control their conductivity. Recognizing a material as a semiconductor involves considering these electronic properties, such as with GaN, B, and ZnO in the given exercise.

Electrical Conductivity

Taking a closer look at electrical conductivity, it's the measure of a material's ability to allow the flow of electric current. Conductivity is dictated by factors such as the presence of free electrons within a material. Materials with high conductivity, such as metals like Lead (Pb), have abundant free electrons that move easily under an electric field, facilitating a strong electric current.

Conversely, insulators have very few free electrons and thus a very high resistance to the flow of electricity. The concept of conductivity not only pertains to metals but also plays a crucial role in understanding the functionality of semiconductors. It gets interesting because semiconductors can have their conductivity fine-tuned. Through doping and the introduction of defects, semiconductors can achieve varying levels of conductivity to suit specific electronic applications, offering a versatility that metals or insulators cannot provide.

Understanding the factors affecting conductivity, including temperature, material composition, and doping, allows us to predict and control the electrical performance of materials, like the adjustment of conductivity in Boron by introducing different types of impurities.

Periodic Table Elements

When exploring materials and their classifications, it's essential to reference the periodic table—a chemist's roadmap. The elements are arranged in an order reflecting their atomic structure, which in turn influences their properties and behaviors. Elements like Boron (B) and Lead (Pb) mentioned in our exercise find their homes in groups 13 and 14, respectively.

Group placement on the periodic table can tell us a lot. For instance, group 13 elements, such as Boron, typically display a mix of metallic and non-metallic properties. This versatility places Boron in the semiconductor category when it's in its pure, crystalline form. On the flipside, Lead, residing in group 14, is known for its metallic characteristics—its malleability, ductility, and high electrical conductivity making it a classic representative of metals.

The periodic table is more than just a collection of elements; it's a tool for predicting how elements behave alone or when combined. This predictive power is what allows scientists and engineers to engineer materials with particular properties, ensuring that when we encounter a compound like ZnO or GaN, we can anticipate its semiconductor behavior based on the properties of the constituent elements from the periodic table.