The reverse saturation current, denoted as I0, can be estimated using the diode equation:
I = I0 * (exp(qV/kT) - 1)
where I is the current through the diode, q is the charge of an electron, V is the voltage across the diode, k is Boltzmann's constant, and T is the temperature in Kelvin.
At room temperature, T = 298 K. We are given that the diode carries a current of 1 mA when a forward bias of 0.15 V is applied. Let's assume that the diode is ideal, meaning that it has no series resistance, so the voltage across the diode equals the forward bias voltage.
Plugging in these values, we get:
1E-3 A = I0 * (exp((1.602E-19 C)(0.15 V) / (1.381E-23 J/K)(298 K)) - 1)
Simplifying, we get:
1E-3 A = I0 * (exp(0.01275) - 1)
1E-3 A / (exp(0.01275) - 1) = I0
I0 = 2.34E-12 A, or approximately 0.23 nA. Therefore, the estimated reverse saturation current at room temperature is 0.23 nA.