From 702d4e732c8e58d107c3943a9da41cdd02fde348 Mon Sep 17 00:00:00 2001
From: Sathish Kumar RK <rksathish09@gmail.com>
Date: Wed, 3 Apr 2019 14:22:39 +0000
Subject: [PATCH] reformulated exercises

---
 src/14_doping_and_devices.md | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/14_doping_and_devices.md b/src/14_doping_and_devices.md
index fe23e206..cca962b5 100644
--- a/src/14_doping_and_devices.md
+++ b/src/14_doping_and_devices.md
@@ -260,14 +260,18 @@ The current flowing through a diode as a function of applied bias voltage is giv
 
 $$ I(V) = I_s(T)\left(e^{\frac{eV}{kT}}-1\right)$$
 
-where $I_s(T)$ is the current flowing through a diode when it is reverse biased i.e. the positive terminal of battery is connected to n-type semiconductor and the negative terminal to p-type. $I_s(T)$ is nearly independent of the applied bias voltage (V) but varies as a function of temperature (T). 
+where $I_s(T)$ is the current flowing through a diode termed as saturation current. $I_s(T)$ is nearly independent of the applied bias voltage (V) but varies as a function of temperature (T). 
 
 <Add I-V plot of pn diode from simon's book>
 
-1. Discuss two possible scenarios by which a pn diode generates current in the reverse biased condition.
-2. How does temperature affect the saturation current $I_s(t)$ in the two possible scenarios? 
-3. Sketch a plot of saturation current as a function of temperature T.
-4. Does two intrinsic semiconductors joined together generates current?
+1. What is the significance of adding dopant atoms to an intrinsic semiconductor? Does two intrinsic semiconductors joined together in the form a p-n diode conducts current?
+
+A p-n diode can be used as a rectifier. When forward biased (positive terminal of the battery is connected to p-type semiconductor and negative terminal is connected to n-type), a p-n diode conducts current. In contrast, when the diode is reverse biased, only negligible current flow occurs which varies as a function of temperature. 
+
+2. Discuss the possible scenarios by which a pn diode generates current in the reverse biased condition.
+3. How does the temperature affects saturation current $I_s(T)$? 
+4. Sketch a plot of saturation current as a function of temperature T.
+
 
 ### Exercise 4: Quantum well heterojunction in detail
 A quantum well is formed from a layer of $GaAs$ of thickness $L$, surrounded by layers of $Al_{x}Ga_{1−x}As$.
-- 
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