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Which of the following processes are crucial for the formation of a p-n junction?
According to the NCERT text, 'Two important processes occur during the formation of a p-n junction: diffusion and drift.'
During p-n junction formation, what is the direction of diffusion of holes?
The NCERT states, '...holes diffuse from p-side to n-side (p → n) and electrons diffuse from n-side to p-side (n → p).' This is due to the concentration gradient.
When an electron diffuses from the n-side to the p-side during p-n junction formation, what does it leave behind on the n-side?
The text mentions, 'When an electron diffuses from n → p, it leaves behind an ionised donor on n-side. This ionised donor (positive charge) is immobile as it is bonded to the surrounding atoms.'
What is the primary cause of the diffusion current across a newly formed p-n junction?
The NCERT states, 'During the formation of p-n junction, and due to the concentration gradient across p-, and n- sides, holes diffuse from p-side to n-side (p → n) and electrons diffuse from n-side to p-side (n → p). This motion of charge carries gives rise to diffusion current across the junction.'
Which region forms on the n-side of a p-n junction due to the diffusion of electrons?
The text describes, 'As the electrons continue to diffuse from n → p, a layer of positive charge (or positive space-charge region) on n-side of the junction is developed.'
The term 'depletion region' in a p-n junction refers to the area where:
The NCERT explains, 'This space-charge region on either side of the junction together is known as depletion region as the electrons and holes taking part in the initial movement across the junction depleted the region of its free charges.'
What is the primary direction of the electric field that develops within the depletion region of a p-n junction?
The text states, 'Due to the positive space-charge region on n-side of the junction and negative space charge region on p-side of the junction, an electric field directed from positive charge towards negative charge develops.' This means from n-side to p-side.
What happens to the electric field strength in the depletion region as the diffusion process continues during p-n junction formation?
The NCERT notes, 'As the diffusion process continues, the space-charge regions on either side of the junction extend, thus increasing the electric field strength and hence drift current.'
In a p-n junction at equilibrium, what is the relationship between diffusion current and drift current?
The text explicitly states, 'This process continues until the diffusion current equals the drift current. Thus a p-n junction is formed. In a p-n junction under equilibrium there is no net current.'
The potential difference developed across the p-n junction at equilibrium, which opposes further flow of carriers, is often called:
The NCERT states, 'Since this potential tends to prevent the movement of electron from the n region into the p region, it is often called a barrier potential.'
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