Which element of group 13 is a soft metal with a low melting point (303K) and is widely used in doping semiconductors and producing solid-state devices such as transistors?

Gallium

The correct answer is option 4. Gallium.

Gallium is a metal in Group 13 of the periodic table, and it shares some characteristics with both metals and nonmetals. Here are some key points about gallium and its relevance in semiconductor technology:

1. Physical Properties: Gallium is a soft metal with a melting point of approximately 303 K (30°C or 86°F), which is just above room temperature. This property makes it unique among the metals in Group 13, as most metals in this group have much higher melting points.

2. Semiconductor Applications:  Gallium is widely used in the electronics industry, particularly in the production of semiconductors and solid-state devices. One significant application is in the production of gallium arsenide (GaAs), a compound semiconductor. Gallium arsenide is employed in the fabrication of various electronic components, including transistors and diodes.

3. Doping Semiconductors:  Gallium is often used as a dopant in the semiconductor industry. Doping involves intentionally introducing impurities into a semiconductor material to alter its electrical properties. By doping silicon or other semiconductors with gallium, engineers can control the conductivity and other characteristics of the material.

4. Low Melting Point Advantage:  The relatively low melting point of gallium is advantageous in certain applications. For example, gallium-based alloys with other metals, like gallium-indium-tin alloys, remain liquid at room temperature. Such alloys are used in some specialized applications, including thermal management systems and soft robotics.

In summary, gallium's unique combination of a low melting point and semiconductor properties makes it a valuable element in the field of electronics and semiconductor technology, playing a crucial role in the production of various electronic devices.