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A semiconductor material can be doped to form a p-n junction (semiconductor diode) - Leaving Cert Physics - Question d - 2006
Question d
A semiconductor material can be doped to form a p-n junction (semiconductor diode). Explain the underlined terms. Name a material used as a semiconductor. The cir... show full transcript
Worked Solution & Example Answer:A semiconductor material can be doped to form a p-n junction (semiconductor diode) - Leaving Cert Physics - Question d - 2006
Step 1
Explain the underlined terms.
Answer
A semiconductor is a material that has a specific level of electrical conductivity that lies between that of a conductor and an insulator. Its conductivity can change significantly with temperature, and it can either conduct or resist electricity depending on conditions, making it a versatile material in electronic devices.
A p-n junction is the interface or boundary between two types of semiconductor material: p-type (positively doped) and n-type (negatively doped). This junction is formed by doping the semiconductor with specific materials that create regions with an abundance of holes (p-type) and electrons (n-type). The behavior of this junction is critical in the functioning of various electronic components, including diodes and transistors.
Step 2
Name a material used as a semiconductor.
Answer
Common materials used as semiconductors include Silicon (Si), Germanium (Ge), Aluminum nitride, Boron nitride, or compounds such as Gallium arsenide. Silicon is the most widely used material in electronic devices due to its optimal electrical properties and abundance.
Step 3
What is observed when the switch is closed? Explain why?
Answer
When the switch is closed, it is observed that:
- Bulb A lights up.
- Bulb B does not light up.
Bulb A lights up because it is in series with the diode that is forward biased, allowing current to flow through it. Conversely, Bulb B does not light because it is connected in reverse bias which prevents current from passing through the diode, resulting in no light being emitted.